Caterpillarchallenger
Caterpillar MT755
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar MT755 is a high-horsepower rubber-track row-crop and tillage tractor built at Jackson, Minnesota under the Challenger nameplate. Caterpillar developed the original Challenger 35/45/55 track-tractor line, then sold the design, assembly, and marketing of the follow-on MT-series to AGCO in 2002 while staying on as a long-term supplier of engines and drivetrain components. Across five generations built from 2002 to 2017, the MT755 carried a 6-cylinder turbo diesel rated 290 hp gross on the original 2002-2004 model, 301 hp on the ACERT-equipped MT755B and MT755C (2005-2011), 327 hp on the AGCO Power-engined MT755D (2012-2013), and 350 hp on the 7-cylinder AGCO Power MT755E (2014-2017). Operating weight runs roughly 13.4-14.1 t (29,500-31,100 lb) depending on generation and track/axle configuration. Every version rides on Caterpillar's Mobil-trac rubber-belt undercarriage, drives through a 16-speed full-powershift transmission with an optional 30-speed creeper, and offers narrow and wide axle/track gauges, a Category III/IIIN drawbar, and an independent 1000-rpm rear PTO.
The biggest split in the lineup is the engine supplier: 2002-2011 machines (MT755, MT755B, MT755C) run the Caterpillar-sourced 8.8-liter block, badged C9 ACERT from the B-series on, while the 2012-2017 MT755D and MT755E moved to AGCO's own 8.4-liter and 9.8-liter blocks with SCR/DEF aftertreatment to meet Tier 4 rules. Hydraulics stayed a closed-center pressure-flow-compensated system throughout, but pump flow and fuel/DEF tank sizing grew with each generation. For buyers and parts sourcing, that means an MT755 is really two different driveline families under one model number, and the correct fluid, filter, and injection-system parts depend on which generation and serial range is in front of you. The tractor stays common in the used market, with working units regularly trading in the 3,000-8,000+ hour range, and because AGCO kept building the MT700 platform in the same Minnesota plant through the MT700E series, parts support and salvage supply for the MT755 remain active even after the line was redesigned under new model numbers after 2017.
Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.
Caterpillar MT755 specifications
Engine
| Engine model / generation | Base MT755 (2001-2006): Caterpillar 8.8 L (537 cu in) turbocharged 6-cylinder diesel. MT755B (2006-2008) and MT755C (2008-2016): Caterpillar C9 ACERT turbocharged, air-to-air aftercooled 6-cylinder, 24-valve diesel. |
| Gross power - base MT755 | 216 kW (290 hp) at 2100 rpm |
| Gross power - MT755B/MT755C (C9 ACERT) | 224.5 kW (301 hp) at 2100 rpm |
| Rated PTO power - MT755B/MT755C | 182.7 kW (245 hp) |
| Displacement | 8.8 L (537 cu in), 6 cylinders inline, 24-valve on the C9 ACERT generation |
| Bore x stroke | 112 mm x 149 mm (4.409 in x 5.866 in) |
| Compression ratio | Base MT755: 16.0:1. C9 ACERT (MT755B/MT755C): 17.1:1 |
| Emissions tier | C9 ACERT generation (MT755B/MT755C) meets Tier 3 emissions. Emissions tier for the earlier pre-ACERT base MT755 is not documented in available sources |
Weights
| Operating/shipping weight - MT755B/MT755C | 14,095 kg (31,075 lb); some configurations run closer to 13,700 kg (30,195 lb) - varies by configuration/series |
| Operating/shipping weight - base MT755 (2001-2006) | 13,399 kg (29,540 lb) |
| Max gross operating weight (ballasted) | up to 16,329 kg (36,000 lb) |
| Ground pressure | not published in available sources |
Dimensions
| Overall length | 591 cm (233 in) - MT755B/MT755C |
| Overall width (outside frame) | 337 cm (133 in) |
| Height to top of cab | 344 cm (135.5 in) |
| Wheelbase | 243 cm (96 in) |
| Ground clearance | 36 cm (14.3-14.4 in) |
| Track gauge (adjustable) | 152-223 cm (60-88 in) on the standard axle; 152-304 cm (60-120 in) and 304-406 cm (120-160 in) available on wide/extended-axle options |
| Track (belt) width options | 36 cm (14 in), 41 cm (16 in), 46 cm (18 in, standard), 64 cm (25 in), 76 cm (30 in) |
Performance
| Transmission | 16 forward / 4 reverse full powershift, push-button control |
| Top travel speed | up to 39.6 km/h (24.6 mph) in high gear (published for MT755B); varies with axle and track configuration |
| Working-speed range | eight of the sixteen forward gears fall between 6.5 and 14.9 km/h (4-9.3 mph) for field work |
| Max drawbar pull (tested) | 13,729 kg (30,267 lb) |
| Drawbar power (tested) | approximately 151-159 kW (203-214 hp), varies by generation and test conditions |
| 3-point hitch lift capacity | 7,257 kg (16,000 lb) measured 610 mm (24 in) behind the ball, Category III/IIIN |
| PTO | rear, 1000 rpm, 1-3/4 in (21-spline) shaft |
Service capacities (summary)
| Fuel tank | 446.6 L (118 US gal) standard; 673.7 L (178 US gal) on wide/extended-axle configuration; up to 787.3 L (208 US gal) optional |
| Hydraulic system | closed-center, pressure/flow-compensated; standard pump flow 136.3 L/min (36 gpm), optional high-flow pump 223.3 L/min (59 gpm); rated total system flow 164.6 L/min (43.5 gpm) at 200 bar (2900 psi) |
| Engine oil (crankcase) capacity | not documented for this chassis installation in available sources - confirm with dealer or service manual |
| Cooling system capacity | not documented for this chassis installation in available sources - confirm with dealer or service manual |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
MT755 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | Not published in publicly available spec sheets for this early-generation MT755 (8.8 L Caterpillar 6-cylinder turbocharged diesel). Confirm exact fill against the dipstick and OMM data plate. | Cat DEO (Diesel Engine Oil), SAE 15W-40 for general/warm-climate use; drop to SAE 10W-30 in cold-ambient starts per the OMM cold-weather viscosity chart. |
| Cooling system | Not documented in publicly available literature for this configuration. Verify against the OMM refill chart or radiator sight gauge. | Cat ELC (Extended Life Coolant), full-strength or 50/50 premix as specified for ambient range; do not mix with conventional green coolant. |
| Fuel tank | 446.6 L (118 US gal) standard, with 88 in rear-axle spacing. 673.7 L (178 US gal) with 120 in or 160 in axle spacing. 787.3 L (208 US gal) with the optional large tank. | No. 2-D diesel fuel (No. 1-D blend permitted below freezing per OMM cold-weather guidance). |
| Transmission (powershift compartment) | Not documented in publicly available literature for this model. Machine uses a 16F/4R full powershift as standard, with a 30F/8R creeper gearbox as an option; capacity varies by which transmission is fitted. | Cat TDTO (Transmission/Drive Train Oil), TO-4 spec. |
| Final drives (each) | Not documented in publicly available literature for this model. | Cat TDTO, TO-4 spec (same fluid family as transmission and hydraulic compartments on this platform). |
| Hydraulic system and tank | Not documented in publicly available literature for this model. Pump is a closed-center, load-sensing, pressure-flow-compensated design rated at roughly 165 L/min (43.5 US gpm) at 200 bar (2900 psi); this is a flow rating, not a reservoir capacity. | Cat TDTO, TO-4 spec (hydraulic and drivetrain compartments share the same fluid spec on this platform). |
| Grease (spec only) | Per standard lubrication interval chart; no numeric capacity applies. | Cat multipurpose grease, NLGI 2 lithium-complex base, for all track, pivot, and driveline grease points. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar MT755 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 50 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
| Every 6,000 h |
|
Servicing the MT755 beyond the schedule
Predictive Maintenance & Fluid Analysis
Pull engine, transmission/final-drive, and hydraulic oil samples on a fixed interval and track wear-metal trends rather than waiting for a fault light, since the MT755 spans both Caterpillar 8.8-liter and AGCO Power 8.4/9.8-liter blocks with different failure signatures. Log track tension pressure at every service; a slow drop off the 2900 psi (200 bar) spec points to a leaking tensioner cylinder before it costs a belt. On DEF-equipped MT755D/E units, watch SCR derates closely. Check guide-lug temperatures with an infrared gun to catch misalignment before it chews through drive lugs.
Corrective & Common Repairs
Expect Mobil-trac rubber belt cuts, chunking, and drive-lug wear from rock and stubble, plus midroller and front-idler rubber wearing thin under the same abuse. Drivewheel grooves round off over time and cause track slip long before the steel underneath cracks. Closed-center pressure-flow-compensated hydraulic valve banks leak most often at the remote quick couplers and the track detensioning port. Swing-link cap bolts loosen or shear on scraper and tillage duty and should be replaced anytime the track comes off, not just when broken.
Overhaul & Rebuild Points
Plan an engine mid-life overhaul around injector and turbocharger condition on either the Caterpillar 8.8-liter or AGCO Power block, guided by oil analysis rather than a fixed hour number. Powershift clutch packs are the next wear point; slipping shifts or hunting shift quality signal a rebuild before the transmission fails outright. Track tensioner cylinders and accumulators need rebuilding once nitrogen precharge will not hold near 2100-2300 psi (145-160 bar). A full undercarriage rebuild, covering idlers, drivewheels, midrollers, and swing links, is normal once rubber wear limits are reached.
Seasonal & Environment Servicing
Before spring planting, run a track alignment check and confirm nitrogen precharge and tension hold at spec after winter storage, since cold contracts hydraulic oil and can mask a slow leak. Service cab HVAC and air intake filters more often in dusty tillage and harvest conditions than the standard interval calls for. Drain the fuel/water separator after long idle periods to clear condensation. In cold climates, verify coolant concentration and block heater operation, and grease all track and hitch pivot points before storage to keep moisture out of the pins.
MT755 common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 1R-0762 | Filter As-Fuel | Fuel system service | Check fitment → |
| 161-1705 | Sensor As-Pressure | Lubrication service | Check fitment → |
| 1R-0716 | Filter As-Engine Oil | Lubrication service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
MT755 fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| E100 | Engine oil pressure signal out of normal range (low oil pressure fault) | Low oil level, worn oil pump, clogged filter, or failed oil pressure sensor | Shut engine down at once, check oil level and condition, inspect sensor and wiring before restart |
| E110 | Engine coolant temperature signal above normal range (overheat) | Low coolant, blocked radiator or screens, fan drive fault, or failed coolant temperature sensor | Idle down and shut off, check coolant level once cool, clear debris from radiator and screens |
| E102 | Turbocharger boost pressure signal out of expected range | Restricted air filter, intake leak, or faulty boost pressure sensor | Inspect and clean or replace the air filter, check intake hoses and clamps for leaks |
| E9131 | Fault on an individual fuel injector circuit; cylinder 1 of the six-cylinder engine (parallel codes cover cylinders 2 through 6) | Injector wiring fault, failed injector solenoid, or driver fault at the engine control module | Check injector harness connections and continuity, have dealer confirm the failed cylinder with diagnostic software before replacing the injector |
| E9072 | Loss of or implausible signal from the engine speed sensor | Damaged sensor, wiring fault, or incorrect sensor air gap | Inspect sensor connector and wiring, check mounting and gap, replace sensor if signal stays absent |
| E168 | System voltage outside normal charging range | Weak or failing battery, loose or corroded terminals, faulty alternator or regulator | Check battery terminals and state of charge, test alternator output, inspect charging circuit wiring |
| D154 | Loss of CAN bus communication between the instrument cluster display and other tractor control modules | Damaged CAN wiring or connector, module power loss, or a control module dropping off the bus | Check main harness connectors and grounds, cycle the key, have dealer scan the bus to isolate the module |
| T4128 | Internal fault in the transmission control unit; transmission defaults to a protected operating mode | Control unit internal fault, corrupted calibration, or a wiring/power supply problem to the control unit | Cycle the key and note if the fault returns immediately; have dealer reflash or replace the control unit if it persists |
| T4174 | Transmission control unit cannot confirm parking brake switch status | Failed brake position sensor, damaged wiring, or a sticking linkage | Inspect the parking brake switch and linkage, check wiring continuity, verify full engagement and release before returning to service |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
MT755 attachments & work tools
Three-point hitch and rear linkage
Rear linkage is an electronically controlled Category III / IIIN (narrow) three-point hitch with integrated track-slip control. Lift capacity is about 7,257 kg (16,000 lb), consistent across B-series and D-series tractors.
Quick-coupler / mounting system
The rear three-point uses a Category III narrow quick-coupler pin and spacing standard, letting the tractor swap mounted tillage and seeding tools without re-pinning each link arm. This Cat III-N coupling is documented in factory-family parts literature covering the MT755 range.
Drawbar for towed (pull-type) work tools
Standard equipment is a swinging drawbar, swings roughly 9 degrees to each side, used as the mounting point for pull-type implements such as chisel plows, rippers, disc harrows, and air-seeder carts.
PTO-driven work tools
Independent rear PTO runs at 1000 rpm standard. PTO output is in the 194-237 kW (260-317 hp) range depending on series - varies by configuration/series - covering PTO-driven carts and rotary implements where fitted.
Hydraulic remote / high-flow kit options
Hydraulics are closed-center, load-sensing, pressure-flow-compensated (PFC). Standard fitment is 4 remote valves, expandable to 6, at a base pump flow near 165 lpm (43.5 gpm) and about 200 bar (2900 psi). A high-flow pump option raises output to roughly 223 lpm (59 gpm) on D-series machines, with later E-series literature citing flows up to about 322 lpm (85 gpm) - varies by configuration/series - needed for hydraulically driven or folding implements such as air drills.
Track (Mobil-trac) width / undercarriage options
Rubber-belt track width offerings for this model span roughly 457-914 mm (18-36 in) across model years and markets, with 635-762 mm (25-30 in) belts the most common fit. Wider belts favor flotation under heavy mounted tillage tools; narrower belts suit tighter row-crop clearance.
Front ballast weighting for mounted implements
Front track-frame idler weight brackets offset heavy rear-mounted or three-point implements. Dealer literature cites a standard set of 8 x 57 kg blocks, expandable up to 24 x 57 kg blocks (12 per side), to help hold the tractor's roughly 60/40 front-to-rear static weight split under load.
Construction/earthmoving factory configuration
Separate from the row-crop tillage package, the manufacturer has offered a specially configured heavy-duty build of this track-tractor family for towing pull-type earthmoving equipment such as pan scrapers, aimed at construction and similar off-farm work rather than field tillage.
All MT755 assemblies by section
Every catalogued assembly group for the Caterpillar MT755. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Air Inlet And Exhaust System
174-1590 Elbow Gp-Air Inlet
| 17***90 | Elbow Group-Air Inlet | 1 |
| 1U***46 | Sealant (For Locations A) | 0 |
| 20***60 | Elbow-Air Inlet | 1 |
173-6107 Elbow Gp-Air Inlet
| 13***53 | Stud; (M8x1.25x82.75-mm)(M8x1.25x82.75-mm) | 8 |
| 17***07 | Elbow Group-Air Inlet | 1 |
| 18***71 | Elbow-Air Inlet | 1 |
165-4444 Manifold Gp-Exhaust
| 11***15 | Stud-Taperlock; (M10x85-mm Oal) | 12 |
| 16***98 | Manifold-Exhaust | 1 |
| 16***11 | Gasket | 6 |
171-4687 Manifold Gp-Exhaust
| 11***15 | Stud-Taperlock; (M10x85-mm Oal) | 12 |
| 16***98 | Manifold-Exhaust | 2 |
| 16***11 | Gasket | 6 |
169-3121 Turbocharger Gp
| 16***21 | Turbocharger Group | 1 |
| 19***46 | Turbocharger Group | 1 |
| 1P***51 | Gasket; (Turbocharger) | 1 |
193-3346 Turbocharger Gp
| 13***02 | Clamp As; (Turbine)(Turbine) | 1 |
| 16***63 | Clamp | 2 |
| 17***91 | Hose; (Wastegate) | 1 |
191-5518 Turbocharger Gp
| 19***94 | Turbocharger Group | 1 |
| 19***18 | Turbocharger Group | 1 |
| 1P***51 | Gasket; (Turbocharger) | 1 |
191-5094 Turbocharger Gp
| 13***01 | Housing-Turbine | 1 |
| 13***02 | Clamp As; (Turbine)(Turbine) | 1 |
| 19***94 | Turbocharger Group | 1 |
206-2947 Turbocharger Gp
| 13***02 | Clamp As; (Turbine)(Turbine) | 1 |
| 16***63 | Clamp | 2 |
| 17***20 | Hose; (Wastegate) | 1 |
206-4013 Turbocharger Gp
| 1P***51 | Gasket; (Turbocharger) | 1 |
| 20***47 | Turbocharger Group | 1 |
| 20***13 | Turbocharger Group | 1 |
Basic Engine
164-6100 Camshaft Gp
| 10***94 | Plate-Thrust | 1 |
| 16***00 | Camshaft Group | 1 |
| 1B***05 | Key; (Woodruff) | 1 |
189-6308 Cover Gp-Cylinder Block
| 18***08 | Cover Group-Cylinder Block | 1 |
| 5F***81 | Gasket To Flywheel Housing Drain Tube Assembly | 1 |
| 5F***59 | Flange | 1 |
183-3649 Cover Gp-Cylinder Block
| 18***49 | Cover Group-Cylinder Block; -Rear | 1 |
| 20***87 | Breather As; (Crankcase) | 1 |
| 21***10 | Gasket | 1 |
166-1775 Cover Gp-Front Housing
| 06***55 | Seal-O-Ring (Id=47.22mm) | 1 |
| 12***57 | Washer; (10.85x19.3x1.27-mm Thk) | 2 |
| 13***22 | Stud | 2 |
216-3047 Cover Gp-Front Housing
| 06***55 | Seal-O-Ring (Id=47.22mm) | 1 |
| 06***97 | Cap-Oil Filler; (Engine Oil) | 1 |
| 12***57 | Washer; (10.85x19.3x1.27-mm Thk) | 2 |
118-1727 Cover Gp-Front Housing
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 13***19 | Seal-Integral; (Integral) | 1 |
| 4W***26 | Cover | 1 |
164-6490 Cover Gp-Valve Mechanism
| 16***90 | Cover Group-Valve Mechanism | 1 |
| 20***39 | Fastener Assem. | 9 |
| 21***01 | Seal-Bulk; (23-Dm)(Valve Mechanism Cover) | 0 |
164-6148 Crankshaft Gp
| 15***39 | Bearing-Main; (Standard) | 7 |
| 16***47 | Crankshaft Assem. | 1 |
| 16***66 | Plate-Thrust | 2 |
204-9538 Cylinder Block As
| 0L***26 | Plug -13mm(.512 In.) Outside Dia. | 2 |
| 17***54 | Bolt-Hex Head; (M16x160mm) | 14 |
| 20***05 | Bearing-Sleeve; (Camshaft) | 2 |
221-3248 Cylinder Block As
| 0L***26 | Plug -13mm(.512 In.) Outside Dia. | 2 |
| 17***54 | Bolt-Hex Head; (M16x160mm) | 14 |
| 20***05 | Bearing-Sleeve; (Camshaft) | 2 |
204-9539 Cylinder Block Gp
| 03***53 | Seal-O-Ring; (08.92mm Id) | 1 |
| 16***24 | Seal-Liner | 6 |
| 19***62 | Liner-Cylinder Block | 6 |
161-3406 Cylinder Block Gp
| 0S***19 | Plug-Cup | 1 |
| 16***06 | Cylinder Block Group | 1 |
| 1W***07 | Sleeve | 2 |
220-1952 Cylinder Block Gp
| 03***53 | Seal-O-Ring; (08.92mm Id) | 1 |
| 16***24 | Seal-Liner | 6 |
| 19***62 | Liner-Cylinder Block | 6 |
201-2180 Cylinder Head As
| 17***88 | Seat-Valve | 12 |
| 17***90 | Seat-Valve | 12 |
| 17***37 | Sleeve-Injector | 6 |
210-5985 Cylinder Head As
| 17***88 | Seat-Valve | 12 |
| 17***90 | Seat-Valve | 12 |
| 21***85 | Cylinder Head As | 1 |
161-3405 Cylinder Head Gp
| 16***05 | Cylinder Head Group | 1 |
| 16***71 | Fastener Group-Cylinder Head | 26 |
| 18***15 | Gasket Assem. | 1 |
210-5987 Cylinder Head Gp
| 16***71 | Fastener Group-Cylinder Head | 26 |
| 18***15 | Gasket Assem. | 1 |
| 21***84 | Cylinder Head Group | 1 |
201-2181 Cylinder Head Gp
| 03***53 | Seal-O-Ring; (08.92mm Id) | 6 |
| 15***06 | Seal-O-Ring; (11.89mm Id) | 5 |
| 16***42 | Valve; (Intake) | 12 |
210-5984 Cylinder Head Gp
| 15***06 | Seal-O-Ring; (11.89mm Id) | 5 |
| 16***42 | Valve; (Intake) | 12 |
| 16***44 | Guide-Valve | 24 |
169-3539 Damper & Pulley Gp
| 15***36 | Pulley-Crankshaft; (8-Groove) | 1 |
| 16***39 | Damper & Pulley Group | 1 |
| 20***19 | Damper As | 1 |
192-3833 Damper & Pulley Gp
| 15***36 | Pulley-Crankshaft; (8-Groove) | 1 |
| 16***21 | Damper Assem. | 1 |
| 19***33 | Damper & Pulley Group | 1 |
202-0103 Drain Gp-Engine Oil
| 20***03 | Drain Group-Engine Oil | 1 |
| 3K***60 | Seal Pilot Manifold On; Seal To Boom Check Valve Drain | 1 |
| 6V***38 | Valve-Shutoff; (Engine Oil Pan Drain) | 1 |
202-2025 Drive Gp-Fan
| 10***26 | Retainer-Bearing | 1 |
| 11***38 | Plate; (Thrust) | 1 |
| 12***56 | Shaft-Fan | 1 |
167-0171 Fastener Gp-Cylinder Head
| 16***71 | Fastener Group-Cylinder Head | 1 |
| 18***63 | Bolt; (M16x2x180-mm) | 1 |
| 9X***68 | Washer; (17.5x30x3.5-mm Thk) | 1 |
169-3106 Fastener Gp-Engine
| 16***06 | Fastener Group-Engine | 1 |
| 4K***90 | Washer; (8.6x17.3x1.6-mm Thk) | 6 |
| 6V***19 | Bolt; (M8x1.25x40-mm) | 6 |
117-2794 Fastener Gp-Flywheel
| 11***94 | Fastener Group-Flywheel; (Flywheel) | 1 |
| 5P***47 | Washer (Bracket To Valve Support) | 8 |
| 9X***21 | Bolt; (Locking) (M16x2.0x45mm) | 8 |
166-1788 Fastener Gp-Front Housing
| 16***88 | Fastener Group-Front Housing | 1 |
| 6V***17 | Bolt; (M8x1.25x30-mm)(Location Z) | 5 |
| 8T***00 | Bolt (M8x1.25x60mm); (M8x1.25x60-mm) | 1 |
173-7123 Fastener Gp-Front Housing
| 17***23 | Fastener Group-Front Housing | 1 |
| 6V***17 | Bolt; (M8x1.25x30-mm)(Location Z) | 4 |
| 8T***00 | Bolt (M8x1.25x60mm); (M8x1.25x60-mm) | 1 |
116-4556 Fastener Gp-Front Housing
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 5P***45 | Washer-Hard; (13.5x25.5x3-mm Thk)(Turbocharger Blanking Plate) | 6 |
| 6V***36 | Bolt; (M12x1.75x70-mm) | 6 |
201-5534 Flywheel Gp
| 15***05 | Pulley-Rear | 1 |
| 16***87 | Gear-Flywheel; (134-Teeth)(Id 405.14mm) | 1 |
| 17***86 | Bolt; (M16x2x115-mm) | 8 |
171-4684 Flywheel Gp
| 15***05 | Pulley-Rear | 1 |
| 16***56 | Flywheel As | 1 |
| 16***87 | Gear-Flywheel; (134-Teeth)(Id 405.14mm) | 1 |
145-9112 Flywheel Gp
| 14***53 | Flywheel As | 1 |
| 14***12 | Flywheel Group | 1 |
| 4N***14 | Gear; (113-Teeth)(Flywheel Starter) | 1 |
155-7918 Gear Gp-Front
| 11***69 | Plate-Thrust | 1 |
| 11***72 | Bearing | 1 |
| 11***19 | Plate-Retaining | 1 |
155-7935 Housing Gp-Flywheel
| 06***55 | Seal-O-Ring (Id=47.22mm) | 1 |
| 15***35 | Housing Group-Flywheel | 1 |
| 1P***69 | Plug-Seal; (Flywheel Housing Drain) | 3 |
165-4446 Housing Gp-Front
| 16***46 | Housing Group-Front | 1 |
| 19***66 | Housing-Front | 1 |
| 1U***46 | Sealant (For Locations A) | 0 |
169-3113 Lifting Gp-Engine
| 16***85 | Plate-Lifting; (Rear) | 1 |
| 16***13 | Lifting Group-Engine | 1 |
| 5P***45 | Washer-Hard; (13.5x25.5x3-mm Thk)(Turbocharger Blanking Plate) | 3 |
193-3293 Lifting Gp-Engine
| 19***93 | Lifting Group-Engine | 1 |
| 19***94 | Plate-Lift Eye | 1 |
| 5P***45 | Washer-Hard; (13.5x25.5x3-mm Thk)(Turbocharger Blanking Plate) | 3 |
187-3884 Mounting Gp-Fan Drive
| 18***84 | Mounting Group-Fan Drive | 1 |
| 18***87 | Support As-Fan | 1 |
| 18***56 | Block | 1 |
187-3076 Pan Gp-Oil
| 18***85 | Pan-Oil; (Engine Oil) | 1 |
| 18***76 | Pan Group-Oil; -Engine | 1 |
| 19***14 | Gasket-Oil Pan; (Engine) | 1 |
188-9141 Piston & Rod Gp
| 15***51 | Skirt-Piston | 1 |
| 16***72 | Bearing-Connecting Rod | 1 |
| 16***97 | Bolt | 2 |
177-7878 Piston Gp
| 17***78 | Piston Group | 1 |
| 18***41 | Piston & Rod Group | 6 |
206-6437 Plug Gp-Engine
| 20***37 | Plug Group-Engine | 1 |
| 3D***24 | O-Ring - For Oil Drain & Level Plug (Items 3 & 7) | 2 |
| 5P***17 | Adapter- To Logic Valve 1u***59 | 1 |
169-3105 Plug Gp-Engine
| 16***05 | Plug Group-Engine | 1 |
| 3D***24 | O-Ring - For Oil Drain & Level Plug (Items 3 & 7) | 1 |
| 6V***49 | Seal-O-Ring (Id=11.89mm); (11.89-mm Id) | 2 |
7e-2313 Drain Gp-Engine Oil
| 3K***60 | Seal Pilot Manifold On; Seal To Boom Check Valve Drain | 1 |
| 7E***13 | Plug Group-Oil Pan | 1 |
| 9X***30 | Plug-Drain; (Magnetic)(Engine Oil Pan) | 1 |
193-1726 Pulley Gp
| 10***26 | Retainer-Bearing | 1 |
| 11***38 | Plate; (Thrust) | 1 |
| 12***56 | Shaft-Fan | 1 |
175-3223 Pulley As-Idler
| 12***90 | Bolt; (M10x1.5) | 1 |
| 12***91 | Cover-Dust | 1 |
| 12***92 | Pulley As-Idler; (8-Groove) | 1 |
213-9321 Rocker Arm Gp -Intake
| 16***49 | Rocker Arm As | 1 |
| 18***65 | Screw-Adjustment; (M10x1.5-Thd) | 1 |
| 21***21 | Rocker Arm Group; -Intake | 1 |
213-9320 Rocker Arm Gp -Exhaust
| 16***47 | Rocker Arm As | 1 |
| 18***65 | Screw-Adjustment; (M10x1.5-Thd) | 1 |
| 21***20 | Rocker Arm Group; -Exhaust | 1 |
178-3899 Seal Gp-Crankshaft
| 11***21 | Seal Group-Crankshaft; (Front) | 1 |
| 17***99 | Seal Group-Crankshaft | 1 |
| 18***61 | Seal Group-Crankshaft; (Rear) | 1 |
185-5334 Support Gp-Engine
| 18***34 | Support Group-Engine; -Front | 1 |
| 20***44 | Support-Engine | 2 |
| 6V***44 | Bolt; (M16x2.0x35mm) | 4 |
171-4685 Support Gp-Engine
| 16***06 | Support-Rear | 1 |
| 17***85 | Support Group-Engine | 1 |
| 1U***46 | Sealant (For Locations A) | 0 |
155-7927 Valve Mechanism Gp
| 13***79 | Rod-Valve Push; (Valve Push) | 12 |
| 15***27 | Valve Mechanism Group | 1 |
| 16***37 | Lifter As-Valve | 12 |
163-2450 Valve Mechanism Gp
| 16***94 | Insert-Rocker Arm | 2 |
| 16***45 | Shaft As-Rocker Arm | 1 |
| 16***46 | Rocker Arm Group; (Exhaust) | 6 |
215-9571 Valve Mechanism Gp
| 16***45 | Shaft As-Rocker Arm | 1 |
| 16***59 | Spring | 6 |
| 16***69 | Stand; (End) | 2 |
Cooling System
188-3826 Cooler Gp-Engine Oil
| 18***26 | Cooler Group-Engine Oil | 1 |
| 20***93 | Gasket | 1 |
| 23***56 | Core As-Oil Cooler; (Engine) | 1 |
187-3066 Cover Gp-Water Outlet
| 18***07 | Seal-Integral | 1 |
| 18***36 | Cover | 1 |
| 18***66 | Cover Group-Water Outlet | 1 |
165-4461 Lines Gp-Water
| 14***11 | Plug Group | 2 |
| 16***61 | Lines Group-Water; -Water Temperature Regulator | 1 |
| 16***24 | Hose | 1 |
208-0440 Lines Gp-Water
| 16***24 | Hose | 1 |
| 19***57 | Gasket; (Water Regulator Housing)(Temperature) | 1 |
| 20***40 | Lines Group-Water; -Water Temperature Regulator | 1 |
205-4013 Plug Gp-Water Lines
| 20***13 | Plug Group-Water Lines; -Coolant | 1 |
| 20***34 | Plug-Cup; (73.38-mm Dia) | 2 |
| 7L***56 | Plug-Cup; (67.03-mm Dia) | 2 |
208-0332 Pump Gp-Water
| 14***88 | Seal As; (Water Pump) | 1 |
| 17***44 | Cover | 1 |
| 17***52 | Shaft As | 1 |
165-4478 Pump Gp-Water
| 16***78 | Pump Group-Water | 1 |
| 18***82 | Pump Group-Water | 1 |
| 2M***53 | Seal--To Seal Brake Housing To Main Housing | 1 |
187-8982 Pump Gp-Water
| 06***69 | Stem | 1 |
| 14***88 | Seal As; (Water Pump) | 1 |
| 17***44 | Cover | 1 |
208-0333 Pump Gp-Water
| 20***32 | Pump Group-Water | 1 |
| 20***33 | Pump Group-Water | 1 |
| 2M***53 | Seal--To Seal Brake Housing To Main Housing | 1 |
Electrical And Starting System
188-3506 Alternator Gp-Charging
| 11***79 | Alternator Group-Charging | 1 |
| 12***40 | Support-Alternator | 1 |
| 13***82 | Support-Alternator | 1 |
117-1379 Alternator Gp-Charging
| 03***12 | Screw-Forming; (10-24x0.5-In) | 3 |
| 10***86 | Stator As-Alternator | 1 |
| 11***79 | Alternator Group-Charging | 1 |
206-6446 Connection Gp-Electrical
| 20***46 | Connection Group-Electrical; -Air Inlet Heater | 1 |
| 20***96 | Cable As | 1 |
| 3T***88 | Terminal-Ring; (4-Ga, 7/16-In Screw) | 1 |
208-2385 Connection Gp-Electrical
| 10***29 | Stud; (M10x1.5-Thd) | 1 |
| 10***03 | Cap; (Stud Protector) | 1 |
| 20***85 | Connection Group-Electrical | 1 |
180-6004 Connection Gp-Electrical
| 10***29 | Stud; (M10x1.5-Thd) | 1 |
| 10***03 | Cap; (Stud Protector) | 1 |
| 18***04 | Connection Group-Electrical | 1 |
165-4468 Control & Mtg Gp-Engine Elek
| 10***28 | Spacer-Special; (12.7x26x28.7-mm Thk) | 2 |
| 16***68 | Control & Mtg Group-Engine Elek | 1 |
| 16***11 | Spacer | 2 |
196-4173 Control Gp-Engine Electronic
| 19***72 | Control Group-Engine Electronic | 1 |
| 19***73 | Control Group-Engine Electronic | 1 |
196-4172 Control Gp-Engine Electronic
| 18***72 | Screw-Pan Head; (No 8-32x9.52-mm)(Wax Coated) | 1 |
| 19***72 | Control Group-Engine Electronic | 1 |
| 7X***15 | Strap; (Grounding) | 1 |
201-0194 Heater Gp-Air Inlet
| 19***59 | Heater As-Air Inlet | 1 |
| 1U***46 | Sealant (For Locations A) | 0 |
| 20***94 | Heater Group-Air Inlet | 1 |
205-6289 Heater Gp-Jacket Water
| 18***36 | Cord As; -Jacket Water Heater | 1 |
| 20***89 | Heater Group-Jacket Water | 1 |
| 20***34 | Plug-Cup; (73.38-mm Dia) | 2 |
4p-1479 Heater Gp-Starting Aid
| 15***11 | Heater As; (Starting Aid) | 1 |
| 1U***46 | Sealant (For Locations A) | 0 |
| 4P***79 | Heater Group-Starting Aid; -Air Inlet Heater | 1 |
177-9816 Mounting Gp-Solenoid
| 17***16 | Mounting Group-Solenoid; -Starting Aid | 1 |
| 19***85 | Bracket | 1 |
| 3E***53 | Washer-Hard; (11x25x3-mm Thk) | 2 |
165-4469 Sensor Gp-Engine
| 11***85 | Seal-O-Ring; (13.94mm Id) | 2 |
| 13***11 | Sensor Group-Temperature; (Transmission Lubrication Oil) | 2 |
| 13***67 | Seal-O-Ring | 1 |
169-3300 Sensor Gp-Speed -Timing
| 16***00 | Sensor Group-Speed; -Engine Timing | 1 |
130-9811 Sensor Gp-Temperature
| 13***11 | Sensor Group-Temperature; (Transmission Lubrication Oil) | 1 |
191-6587 Sensor Gp-Temperature -Engine Oil
| 15***43 | Sleeve; (2.8-Dm) | 0 |
| 15***61 | Wedge-Plug Lock; (2-Pin) | 1 |
| 15***70 | Kit-Connecting Plug; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
207-1524 Starting Motor Gp-Electric
| 03***23 | Bolt; (1/4-28x1-In) | 5 |
| 20***89 | Kit-Solenoid; (12-Volt)(Starting Motor) | 1 |
| 20***24 | Starting Motor Group-Electric | 1 |
101-8936 Starting Motor Gp-Electric
| 10***36 | Starting Motor Group-Electric | 1 |
| 15***25 | Gasket | 1 |
| 20***24 | Starting Motor Group-Electric | 1 |
175-2303 Switch Gp-Magnetic -Air Inlet Heater
| 01***80 | Lockwasher | 2 |
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 17***03 | Switch Group-Magnetic; -Air Inlet Heater | 1 |
209-1953 Wiring Gp-Electronic Control
| 00***35 | Protector | 1 |
| 10***20 | Plug As-Connector; (2-Pin) | 1 |
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 2 |
188-9869 Wiring Gp-Electronic Control
| 00***35 | Protector | 1 |
| 01***80 | Lockwasher | 2 |
| 10***20 | Plug As-Connector; (2-Pin) | 1 |
Engine Arrangement
177-1414 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
177-1420 Engine Ar
| 10***36 | Starting Motor Group-Electric | 1 |
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***94 | Fastener Group-Flywheel; (Flywheel) | 1 |
179-4952 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
177-1416 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
177-1418 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
179-4954 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
179-4956 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
179-4958 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
194-4160 Engine Ar
| 11***56 | Fastener Group-Front Housing; (Housing) | 1 |
| 11***27 | Cover Group-Front Housing; -Accessory Drive | 1 |
| 16***90 | Cover Group-Valve Mechanism | 1 |
177-1419 Engine Ar-Core
| 15***18 | Gear Group-Front | 1 |
| 15***27 | Valve Mechanism Group | 1 |
| 16***06 | Cylinder Block Group | 1 |
194-4161 Engine Ar-Core
| 15***18 | Gear Group-Front | 1 |
| 15***27 | Valve Mechanism Group | 1 |
| 16***06 | Cylinder Block Group | 1 |
177-1415 Engine Ar-Core
| 15***18 | Gear Group-Front | 1 |
| 15***27 | Valve Mechanism Group | 1 |
| 16***06 | Cylinder Block Group | 1 |
177-1421 Engine Ar-Core
| 15***18 | Gear Group-Front | 1 |
| 15***27 | Valve Mechanism Group | 1 |
| 16***05 | Cylinder Head Group | 1 |
177-1417 Engine Ar-Core
| 15***18 | Gear Group-Front | 1 |
| 15***27 | Valve Mechanism Group | 1 |
| 16***06 | Cylinder Block Group | 1 |
Frame And Body
206-5947 Mounting Gp -Solenoid
| 20***46 | Bracket | 1 |
| 20***47 | Mounting Group; -Solenoid | 1 |
| 3E***53 | Washer-Hard; (11x25x3-mm Thk) | 2 |
Fuel System
217-2570 Injector Gp-Fuel
| 10***07 | Seal-O-Ring; (Fuel System) | 1 |
| 14***03 | Seal-O-Ring; (Fuel System) | 1 |
| 14***40 | Ring-Backup; (37.36mm Od), Flasher Switch; Hazard, Replaces 421164a1, Flasher Switch | 1 |
236-0962 Injector Gp-Fuel
| 10***07 | Seal-O-Ring; (Fuel System) | 1 |
| 14***03 | Seal-O-Ring; (Fuel System) | 1 |
| 14***40 | Ring-Backup; (37.36mm Od), Flasher Switch; Hazard, Replaces 421164a1, Flasher Switch | 1 |
204-7454 Lines Gp-Fuel
| 03***42 | Elbow Hose Assembly To | 1 |
| 03***47 | Elbow-Filtered Fuel From Based Assembly | 2 |
| 12***33 | Clip | 1 |
189-3803 Lines Gp-Fuel Filter
| 00***15 | Insert | 1 |
| 03***42 | Elbow Hose Assembly To | 1 |
| 03***47 | Elbow-Filtered Fuel From Based Assembly | 1 |
172-5780 Pump Gp-Unit Injection
| 17***80 | Pump Group-Unit Injection | 1 |
| 19***20 | Bolt-Socket Head; (M8x1.25x63-mm) | 2 |
| 21***70 | Injector Group-Fuel | 1 |
166-1759 Pump Gp-Unit Injection
| 16***59 | Pump Group-Unit Injection | 1 |
| 17***80 | Pump Group-Unit Injection | 6 |
204-4944 Pump Gp-Unit Injector Hyd
| 20***44 | Pump Group-Unit Injector Hydraulic | 1 |
165-4450 Pump Gp-Unit Injector Hyd
| 03***50 | Elbow (Check Valve Drain Tube) | 1 |
| 15***06 | Seal-O-Ring; (11.89mm Id) | 3 |
| 15***07 | Seal-O-Ring | 2 |
Lubrication System
206-6441 Filter Gp-Engine Oil
| 1R***16 | Filter As-Engine Oil; (Standard Efficiency) | 1 |
| 20***62 | Seal | 1 |
| 20***41 | Filter Group-Engine Oil | 1 |
183-3700 Filter Gp-Engine Oil
| 03***53 | Seal-O-Ring; (08.92mm Id) | 1 |
| 18***56 | Base As-Oil Filter | 1 |
| 18***00 | Filter Group-Engine Oil | 1 |
187-3077 Fumes Disposal Gp
| 18***77 | Fumes Disposal Group | 1 |
| 19***31 | Bracket | 1 |
| 19***10 | Hose-Fumes Disposal | 1 |
201-5535 Fumes Disposal Gp
| 12***71 | Clamp-Hose | 1 |
| 1D***64 | Spacer; (15.8x21.34x25-mm Thk) | 1 |
| 20***35 | Fumes Disposal Group | 1 |
176-5328 Gauge Gp-Oil Level (Dipstick)
| 17***28 | Gauge Group-Oil Level (Dipstick); -Engine | 1 |
| 18***14 | Gauge-Oil Level; (Dipstick, Engine) | 1 |
| 18***16 | Tube As-Guide; (Rh) | 1 |
187-0710 Gauge Gp-Oil Level (Dipstick)
| 18***10 | Gauge Group-Oil Level (Dipstick); -Engine | 1 |
| 18***16 | Tube As-Guide; (Rh) | 1 |
| 19***33 | Gauge-Oil Level; (Dipstick, Engine) | 1 |
192-2833 Lines Gp-Engine Oil
| 03***34 | Seal-O-Ring | 1 |
| 19***33 | Lines Group-Engine Oil | 1 |
| 19***52 | Gasket | 1 |
188-3028 Lines Gp-Engine Oil
| 16***80 | Tube As | 1 |
| 18***28 | Lines Group-Engine Oil | 1 |
| 19***74 | Elbow-Outlet | 1 |
165-4465 Lines Gp-Turbocharger Oil
| 16***65 | Lines Group-Turbocharger Oil | 1 |
| 16***66 | Tube As | 1 |
| 18***98 | Connector As | 1 |
188-8840 Lines Gp-Turbocharger Oil
| 18***99 | Connector As | 1 |
| 18***40 | Lines Group-Turbocharger Oil | 1 |
| 18***41 | Hose As | 1 |
195-8098 Pump Gp-Engine Oil
| 19***98 | Pump Group-Engine Oil; (Engine Oil) | 1 |
| 21***22 | Pump As-Engine Oil | 1 |
| 21***46 | Gerotor Pump Group | 1 |
Operator Station
188-3507 Compressor Gp-Refrigerant
| 12***37 | Support-Compressor | 1 |
| 18***07 | Compressor Group-Refrigerant | 1 |
| 2Y***29 | Nut-Hard; (M10 X 1.5) | 2 |
MT755 serial number reference
The PIN/serial plate is riveted to the main tractor frame on the front left side, ahead of the cab. Read the first three characters as the model and generation letter prefix and the digits that follow as the sequential unit number within that prefix's parts book. For the MT755 that family prefix is ALM whether the machine carries a Caterpillar or a Challenger brand plate. A low serial number alone does not confirm generation - a B-series machine restarts numbering near the bottom of its own range, so confirm which parts book (A-series vs B-series) the serial belongs to, or check with your dealer.
| Prefix | Identifies | Notes |
|---|---|---|
| ALM | MT755, original/first-generation (pre-B), roughly 2002 through 2004-2006 model years | Built by Challenger (AGCO) in Jackson, Minnesota, with the Caterpillar 8.8 L (537 cu in) six-cylinder turbo diesel, 16.0:1 compression. Serials under this prefix run from roughly ALM20000 for the 2002 model year, ALM30000 for 2003, ALM40000 for 2004, up through 59999. Some units of this era carry Caterpillar-brand decals as an alternate to Challenger decals within the same parts book - AGCO built the tractor and supplied it to Caterpillar dealers under the Caterpillar Challenger nameplate, so the same serial can appear under either brand. |
| ALM | MT755B, second-generation update, roughly 2005/2006 through 2008 model years | Same Jackson, Minnesota assembly. Compression ratio rises to 17.1:1 versus 16.0:1 on the earlier tractor, reflecting a Tier 3 emissions update on the same 8.8 L (537 cu in) Caterpillar six-cylinder diesel. Serial numbering under this prefix restarts near the bottom of the range (ALM00006 and up) for the B-series parts book - do not confuse a low ALM serial with the earlier first-generation machine. Check which parts book (A-series vs B-series) the number falls in before ordering. |
Frequently asked questions
What engine does the Caterpillar MT755 use?
It depends on the generation. The 2002-2004 MT755 and the 2005-2011 MT755B/MT755C run a Caterpillar-sourced 8.8-liter (537 cu in) turbocharged 6-cylinder diesel, gross-rated 290-301 hp and badged C9 ACERT on the later two. The 2012-2013 MT755D switched to an AGCO Power 8.4-liter 6-cylinder rated 327 hp, and the 2014-2017 MT755E used an AGCO Power 9.8-liter 7-cylinder rated 350 hp. Confirm which generation you have from the serial number before ordering engine parts.
What is the operating weight of the MT755?
Operating weight runs roughly 13.4-14.1 t (29,500-31,100 lb) depending on generation, track width, and axle/ballast configuration. The original MT755 sits toward the lighter end near 13.4 t (29,500 lb); the MT755B and MT755C are the heaviest at about 14.1 t (31,100 lb); the MT755E settles back to roughly 13.7 t (30,100 lb). Treat any single figure as an estimate and weigh the specific unit if the number matters for transport or ground pressure.
What replaced the Caterpillar MT755?
Within its own family, the MT755 line ended with the MT755E in 2017 when AGCO redesigned the whole MT700 rubber-track platform under new model numbers. In markets where AGCO retired the Challenger badge, the equivalent track tractors continued as Fendt-branded machines built on the same AGCO driveline. The MT755 itself succeeded Caterpillar's own Challenger 55 row-crop track tractor, built before Caterpillar sold the MT-series design and assembly business to AGCO in 2002.
What MT755 owners discuss
What's the track tensioning system like on the MT755, and what should operators watch for?
Track tension is set through a nitrogen-charged accumulator and hydraulic ram, with pressure readable off the cab monitor screen. Cold weather makes the nitrogen contract, so a low-tension alarm right at cold start often clears once the machine warms up rather than pointing to an actual leak. A persistent low-tension warning should still be treated as a shutdown condition - running with tension out of spec accelerates bushing, sprocket, and idler wear (a loose track can ratchet over the sprocket, an overtight one loads the idlers hard). Have your dealer verify accumulator charge and pressure sensor calibration before assuming a leak.
What's the most common undercarriage wear point owners report?
Mid-roller/bogie wheel bearings and seals are the recurring weak spot - leaking wheel oil eats the bearings within a couple of seasons if it's ignored. Oil viscosity matters here: some owners found lightweight oil (10W) leaks out and switched to 30W or 80W-90, with synthetic SAE 50 favored by some dealers. Older flat-track machines ride on airbags at the bogie stations, roughly 550-620 kPa (80-90 psi), that lose pressure with age and give a noticeably rougher ride once soft. Track and bar life itself varies a lot by conditions and tension discipline - some units need bars and idlers redone by around 1000 hours from cracking or rubber peeling, while well-kept examples run the same tracks well past 3000 hours at 60% wear.
Is the reaction arm bearing really the tractor's known weak point?
Yes, it's the most consistently cited mechanical weak spot on this drivetrain. The reaction arm bearing housings get their oil changed on the same interval as engine oil, and owners check daily for oil weeping onto the drive belt as an early warning sign. Pulling the magnetic drain plug periodically is standard practice: fine metal fuzz is normal, larger chunks mean bearing wear is underway. A failed reaction arm bearing can send debris into the final drive, so have your dealer verify bearing condition (oil sample or plug inspection) before the machine is worked hard.
Does the engine change across MT755 model years, and does that affect known issues?
Yes, and it matters when troubleshooting. The original MT755 (2002-2004) and MT755B (2005-2008) run a Caterpillar 8.8-liter C9 inline-six, stepping up to a C9 ACERT version of the same block by the MT755C (2009-2011). On these C9-based tractors, injector wear is the recurring complaint - misfire or rough idle that shows up once the engine is warm, sometimes with a puff of unburnt fuel smoke, usually clearing above roughly 1500 rpm. Cold-start behavior also varies a bit by series, with some owners finding the earlier C9 units start easier than later ones. From the MT755D (2012-2013) onward, Caterpillar power was dropped in favor of an AGCO Power/Sisu diesel with selective catalytic reduction, which trades the older C9 injector-wear pattern for DEF consumption and aftertreatment upkeep instead. Confirm which engine is actually fitted rather than assuming by model year alone.
What electrical or sensor issues come up most often?
Cab A/C blower motors are a known wear item that doesn't last as long as the rest of the cab electronics. Keep the A/C condensate drain tube clear - a control module sits in that part of the cab and doesn't tolerate water intrusion, and a clogged drain has been blamed for unrelated-looking electrical gremlins afterward. Brake-accumulator-low and general engine fault codes also turn up on tired examples; treat any string of active codes on a used machine as a reason to have the dealer pull a full code history rather than just clearing them and moving on.
Any known transmission quirks on the powershift?
The full-powershift transmission is generally well regarded, but the shift control handle itself is a known failure point - buttons on the handle can stop responding, and the whole handle assembly typically needs replacing rather than being repaired piecemeal. Run every gear and range during a test drive; intermittent button response is a known symptom on its own and isn't necessarily a sign of internal transmission trouble.
What should a buyer check before purchasing a used MT755?
Walk the undercarriage first: bar wear, idler and bogie wheel play, and whether tracks or wheels show a partial rebuild (new bars with old bogie wheels is common and not automatically a red flag). Check the reaction arm bearing plugs for metal and the belt area for oil weeping. Confirm which engine generation is fitted - Cat C9/C9 ACERT versus the later AGCO Power SCR diesel - since parts sourcing and DEF requirements differ between them. Cycle the transmission through every gear for clean, consistent shifting, and check for active or recent fault codes, especially brake accumulator and track tension warnings. Test the A/C and confirm the cab drain tube is clear. Cross-check the hour meter against undercarriage and reaction-arm wear - a low-hour tractor with heavily worn bogies or bearings points to hard use or deferred maintenance. Have your dealer verify accumulator charge, engine fault history, and undercarriage measurements before finalizing an offer.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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