Caterpillar TH55-E70
Maintenance schedule, common problems & OEM parts breakdown
The Cat TH55-E70 is not a complete machine. It is an off-highway well-service transmission built for oilfield pressure-pumping (frac) duty, sold and mounted as a standalone driveline component rather than a self-contained unit with its own engine. It bolts to a customer-selected engine, Cat 3512C HD, 3516C HD, or 3516D HD, or a Cummins QSK50/QSK60, or an MTU 12V4000/16V4000, through an SAE C/J744 pump drive and SAE #0 flywheel input, rated for input power up to roughly 3300 hp. Internally it runs a seven-speed forward, no-reverse powershift gearbox with a deep 6.25:1 first gear, an integral torque converter at roughly a 2.23:1 stall ratio, and Cat's electro-hydraulic ECPC clutch control. It sits in the same off-highway transmission family as the smaller TH31 and TH35 models and the TH48-E70, scaled up for the highest-horsepower frac spreads, and stands alongside its closest sibling, the nine-speed TH55-E90, which trades first-gear depth for tighter step ratios through the working pump range on the same base spec sheet. Cat does not publish a standalone operating weight for the unit apart from its engine and pump package.
The TH55 platform's gearing and clutch architecture trace back to Cat's own mining-truck drivetrains, a lineage that reached volume production in the 793 haul truck line in the early 1990s, before Caterpillar adapted the design for well-service duty in the early 2000s at the request of pressure-pumping customers who wanted engine-grade durability in a transmission. Since then the line has moved through running-production updates visible mainly as serial-prefix changes, from earlier JW7 and THE ranges to the current PCJ prefix, rather than a clean generational redesign; the core 7F/0R architecture and ECPC control have stayed constant throughout. That mining-truck heritage is why the TH55-E70 matters in the used and parts market today. Cat markets it as outlasting typical oilfield transmissions by several times over, yet the shock-loaded, high-cycle nature of frac-fleet duty still keeps a steady stream of cores moving through Cat's reman exchange program, available since 2020 and including cross-exchange to a TH55-E90 core. Clutch packs, torque converter internals, and ECPC control components are the parts most often traded on units coming off service.
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 TH55-E70 specifications
Engine
| Compatible engines (optimized powertrain) | Cat 3512C HD and 3516D HD; Cummins QSK50 and QSK60; MTU 12V4000 and 16V4000 |
| Gross input power | 2461 kW (3300 hp) |
| Gross input torque | 12 677 N·m (9350 lb-ft) |
| Rated input speed | 1900 rpm |
| Maximum input speed | 1970 rpm |
| Emissions tier | Not published for the transmission itself — emissions rating follows whichever paired engine is installed. |
Weights
| Transmission dry weight | 2917 kg (6430 lb) |
| Engine/transmission coupling weight | 136 kg (300 lb) |
| Installed dry weight (approx.) | 3053 kg (6730 lb) |
Dimensions
| Length of drive train (without adapter) | 1961 mm (77 in) |
| Overall length | 2137 mm (84 in) |
| Width | 1246 mm (49 in) |
| Height | 1288 mm (51 in) |
Performance
| Forward/reverse gears | 7 forward / 0 reverse |
| Gear ratios, 1st through 7th forward | 6.25, 4.59, 3.38, 2.48, 1.83, 1.36, 1.00 |
| Torque converter | Integral torque converter, stall torque ratio 2.23 |
| Input/output rotation | Counterclockwise on both input and output, viewed from rear |
| Maximum PTO power | 112 kW (150 hp) at 1900 rpm; auxiliary pump drive limited to 15 kW (20 hp) at 1900 rpm until the driven device is approved |
| Travel speed / gradeability | Not applicable — this is a stationary well-service drivetrain component, not a self-propelled machine. |
Service capacities (summary)
| Hydraulic/transmission oil fill capacity | Approx. 189 L (50 gal); actual capacity depends on cooler size, line routing, and installation |
| Oil specification | Cat Transmission/Drive Train Oil-4 (TDTO) or equivalent |
| Filter type | 6-micron synthetic, cartridge, remote mount |
| Oil temperature limits | Continuous 90°C (195°F); maximum operating 99°C (210°F) |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
TH55-E70 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Transmission and integral torque converter (system oil fill, incl. filter) | approx. 189 L (50 US gal) total system fill; actual volume varies by cooler size, oil lines, and installation — figure applies to both the TH55-E70 and TH55-E90 well-service transmission line | Cat TDTO (Transmission/Drive Train Oil-4), meeting Cat TO-4 performance requirements. Viscosity grade by ambient/sump temperature: SAE 10W for cold-start conditions, SAE 30 for moderate ambient (roughly 0 to 35-40 C / 32-104 F), SAE 50 for sustained high heat (up to about 60 C / 140 F). Where wide swings or extreme cold service are expected, Cat TDTO-TMS full-synthetic multi-season oil is the arctic-capable option, holding pumpability down to roughly -40 C (-40 F). Oil is filtered through a 6-micron synthetic cartridge, remote-mounted filter. |
| Engine, cooling system, fuel tank, hydraulic implement system, final drives/axles | not applicable to this product | The TH55-E70 is sold as a standalone oilfield well-service transmission, not a complete self-propelled machine. It has no engine, cooling system, fuel tank, or axle/differential of its own — it is factory-matched behind a customer-selected power unit (Cat 3512C HD, Cat 3516C HD, Cummins QSK50, Cummins QSK60, MTU 12V4000, or MTU 16V4000). Fluid recommendations for those systems follow the paired engine's own O&M manual, not the transmission's. |
| Grease points | none published | No external grease-fitting schedule is documented for this transmission in available service literature; the unit is treated as a sealed driveline component serviced primarily through oil sampling and change intervals rather than periodic greasing. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar TH55-E70 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 TH55-E70 beyond the schedule
Predictive Maintenance & Fluid Analysis
TDTO oil sampling is the core predictive tool for this transmission. Samples pulled at the drain port track wear metals from the ECPC clutch packs and the integral torque converter, plus TBN and viscosity breakdown from frac-duty heat cycling. Log stall speed, clutch modulation pressure, and ECPC solenoid response through Cat ET at each interval and compare against baseline. A drifting stall ratio or slow solenoid response shows up in the data before a shift feels rough. Water or coolant traces in a sample flag an immediate case and cooler check.
Corrective & Common Repairs
Common corrective work on the TH55-E70 centers on the ECPC control system and its interfaces, not on engine components, since this is a standalone transmission. Typical repairs include ECPC solenoid pack replacement when shift quality or modulation pressure drifts out of tolerance, harness connector repair where vibration on a frac-trailer skid chafes wiring near the case, cooler-line and filter-head seal leaks at the cartridge filter, and output coupling wear at the pump-drive interface from cyclic loading during pumping stages.
Overhaul & Rebuild Points
Cat literature credits the TH55-E70 with a 30,000 to 40,000 hour service life between rebuilds, well beyond typical powershift transmissions, but frac-duty shock loading can pull that forward on hard-run units. Overhaul-point checks focus on clutch pack plate wear allowance across all seven forward ranges, torque converter impeller and turbine wear, gear-train backlash in the 6.25:1 first-gear set, and SAE #0 flywheel housing and adapter fatigue. Cat Reman offers a factory-rebuilt exchange unit, including cross-exchange to a TH55-E90 core, as an alternative to an in-house teardown.
Seasonal & Environment Servicing
Ambient temperature drives TDTO grade choice on this transmission: SAE 10W, 30, or 50 by season, or Cat TDTO-TMS synthetic where a well site runs across a wide range or into arctic cold, extending change intervals and easing cold-start ECPC response. Clean the cooler core and check fin packing before summer pumping stages, since a frac-site pad throws more airborne debris than a shop-based application. Verify breather function on dusty locations to prevent case pressure buildup, and check cooler lines and connector seals for sand or grit ingestion.
TH55-E70 common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 1D-4540 | Bolt,Machine Fuel Filter Mounting | Fuel system service | Check fitment → |
| 1H-5514 | Bolt,Machine Engine Oil Filter Assembly | Lubrication service | Check fitment → |
| 1R-1809 | Filter Element-Oil | Lubrication service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
TH55-E70 fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CID 0127 (FMI 03/04) | Transmission Oil Pressure Sensor circuit reading voltage above or below normal range | Failed or miswired pressure sensor, damaged harness connector, or low transmission oil level causing an out-of-range signal | Check transmission oil level and sensor connector for corrosion/damage before replacing the sensor |
| CID 0826 (FMI 03/04) | Torque Converter Oil Temperature Sensor circuit voltage above or below normal range | Faulty temperature sensor or open/shorted wiring between the sensor and the transmission ECM | Inspect wiring and connector, then verify sensor resistance against the service manual spec before replacement |
| CID 0671 (FMI 02) | Transmission Output Speed Sensor signal erratic, intermittent, or incorrect | Damaged tone wheel, sensor air-gap out of spec, or intermittent wiring connection | Inspect sensor mounting and air gap, then check harness continuity before replacing the sensor |
| CID 0147 (FMI 03/04) | Lockup/Converter Clutch Pressure Sensor circuit voltage above or below normal range | Sensor failure or wiring fault feeding an out-of-range signal to the ECPC control logic | Verify sensor supply voltage and connector integrity, then test the sensor per the transmission troubleshooting manual |
| CID 0631 (FMI 05/06) | Transmission Clutch No. 1 Solenoid (ECPC modulating valve) open circuit or shorted circuit | Solenoid coil failure, damaged harness, or connector corrosion in the clutch modulating valve circuit | Measure solenoid coil resistance and check wiring per the Electronic Clutch Pressure Control test procedure before replacing the valve |
| CID 0632 (FMI 05/06) | Transmission Clutch No. 2 Solenoid (ECPC modulating valve) open circuit or shorted circuit | Solenoid coil failure, damaged harness, or connector corrosion in the clutch modulating valve circuit | Measure solenoid coil resistance and check wiring per the Electronic Clutch Pressure Control test procedure before replacing the valve |
| CID 0126 (FMI 00) | Transmission Oil Filter Differential Pressure above normal - filter restriction | Clogged transmission oil filter or cold, high-viscosity oil restricting flow at startup | Check oil temperature and condition, then replace the transmission filter if restriction persists after warm-up |
| CID 0132 (FMI 03/04) | Transmission Pilot Pressure Supply Sensor circuit voltage above or below normal range | Sensor failure, low pilot pressure from pump wear, or wiring fault | Confirm pilot system pressure with a gauge, then inspect sensor wiring before replacing the sensor |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
TH55-E70 attachments & work tools
Product type correction
TH55-E70 is a Cat well service (oilfield) transmission for pressure-pumping duty, not a telehandler. It has no bucket/fork/grapple work-tool line; its "attachments" are driveline and PTO/pump-drive interfaces.
Integral pump drive (PTO)
Built-in independent pump drive in an SAE C, J744 pattern powers the well-service pump directly off the transmission, removing the need for a separate third-party PTO. Mounting location and rated power are set per installation.
Input (flywheel) connection
Input side uses an SAE #0 flywheel housing to mate to the prime mover. Any structural (frame-mounted) application of the housing needs Caterpillar engineering approval.
Output connection
Output side uses a flange-type connection to the driven equipment. As with the input housing, structural use of the output connection is subject to Caterpillar approval.
Compatible prime movers
Factory-matched to Cat 3512C and 3516C (HD arrangements), Cummins QSK50 and QSK60, and MTU 12V4000/16V4000 diesels, spanning up to about 2462 kW (3300 hp) gross input at 1900 rpm and roughly 12 677 N·m (9350 lb-ft) input torque.
Cooling package
Runs on Cat TDTO (Transmission/Drive Train Oil) with two external oil cooler lines; total hydraulic fill is about 189 L (50 gal) but varies with cooler size, line length, and installation. A 6-micron synthetic remote-mount cartridge filter is standard.
Clutch and electronic control
Electro-hydraulic, fully modulated, oil-cooled multidisc clutches run through Cat Electronic Clutch Pressure Control (ECPC), governed by an ECU on a SAE J1939 data link, 24V system. An integral torque converter, 2.23 stall ratio, is built in.
Gear configuration variants
The E70 is a 7-forward, 0-reverse unit with an industry-deep first gear (6.25:1), aimed at very low flow-rate work such as pump-down or coil tubing. The sibling TH55-E90 shares the same first seven ratios but adds two more forward gears (9F/0R, first gear 4.67:1) for finer control across the full pumping range; specify by duty cycle, not interchangeably.
Optional/factory equipment
Cat literature lists an "optional equipment" category for this transmission without public detail on scope; treat guarding, PTO cover, and mounting-kit specifics as installation- and dealer-configured rather than standardized.
All TH55-E70 assemblies by section
Every catalogued assembly group for the Caterpillar TH55-E70. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Basic Engine
303-4143 Fastener Gp-Coupling
| 30***43 | Fastener Group-Coupling, Line | 1 |
| 6V***88 | Nut-Full (1/2-13 Thd); (1/2-13-Thd)(Full) | 4 |
| 7X***25 | Bolt (1/2) (63.5mm Thick) | 4 |
296-6515 Flywheel Gp
| 13***01 | Bolt; (M16x2x80-mm) | 12 |
| 28***80 | Washer; (16.3x31.5x1.75-mm Thk) | 12 |
| 29***06 | Flywheel | 1 |
Electrical And Starting System
329-3333 Electronics Gp-Power Train
| 32***25 | Software Group-Power Train | 1 |
| 32***26 | Service Group-Power Train | 1 |
| 32***33 | Electronics Group-Power Train | 1 |
189-5746 Sensor Gp-Speed
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 14***36 | Pin-Connector; (14-Ga To 18-Ga) | 2 |
| 17***49 | Strap; (Marker) | 1 |
183-8597 Sensor Gp-Speed
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 17***49 | Strap; (Marker) | 1 |
| 18***97 | Sensor Group-Speed; -Transmission Output | 1 |
196-1185 Sensor Gp-Speed
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 17***49 | Strap; (Marker) | 1 |
| 18***35 | Pin-Connector; (16-Ga To 18-Ga) | 2 |
122-8863 Sensor Gp-Speed
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 12***63 | Sensor Group-Speed | 1 |
| 17***49 | Strap; (Marker) | 1 |
134-2252 Sensor Gp-Temperature
| 10***03 | Kit; (Receptacle) (3-Pin) (Includes Receptacle As & Wedge) | 1 |
| 13***52 | Sensor Group-Temperature; -Transmission Oil-Xmsn, Torque Converter | 1 |
| 3E***71 | Wedge; (Receptacle Lock) (3 Pin) | 1 |
164-7577 Switch Gp-Bypass
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 16***77 | Switch Group-Bypass; -Xmsn Lubrication Supply Filter-Xmsn Lubrication Charge Filter-Hoist Screen-Tc, Front Brake Cooling-Transmission Oil Filter-Rear Axle Oil Filter | 1 |
| 18***35 | Pin-Connector; (16-Ga To 18-Ga) | 2 |
269-8146 Wiring Gp-Transmission
| 0S***17 | Bolt --Use Open Hole In Compressor Body | 4 |
| 10***01 | Kit; (Receptacle) (12-Pin) (Includes Receptacle As & Wedge) | 1 |
| 10***03 | Kit; (Receptacle) (3-Pin) (Includes Receptacle As & Wedge) | 1 |
Power Train
249-2304 Base Gp-Oil Filter -Transmission
| 13***98 | Spring | 1 |
| 16***77 | Switch Group-Bypass; -Xmsn Lubrication Supply Filter-Xmsn Lubrication Charge Filter-Hoist Screen-Tc, Front Brake Cooling-Transmission Oil Filter-Rear Axle Oil Filter | 1 |
| 24***04 | Base Group-Oil Filter; -Transmission | 1 |
269-8134 Case & Parts Gp-Planetary
| 03***06 | Seal (Use As Required) | 1 |
| 0S***09 | Bolt (3/4") Filler Tube Assembly To Transfer Drive Case | 26 |
| 10***29 | Retainer | 1 |
292-0048 Control Gp-Transmission Hyd
| 10***02 | Kit-Receptacle; (2-Pin)(Engine Sensor Wiring Harness) | 1 |
| 13***00 | Clip; (Tab) | 1 |
| 13***89 | Clip; (Ladder) | 7 |
284-9298 Coupling Gp-Flexible
| 13***01 | Bolt; (M16x2x80-mm) | 12 |
| 28***80 | Washer; (16.3x31.5x1.75-mm Thk) | 12 |
| 28***35 | Seal-O-Ring | 1 |
285-7262 Coupling Gp-Flexible
| 28***35 | Seal-O-Ring | 1 |
| 28***91 | Coupling As | 1 |
| 28***95 | Bearing-Sleeve | 1 |
296-0675 Cover Gp-Shipping
| 29***75 | Cover Group-Shipping | 1 |
| 6H***17 | Bolt,Machine Damper Use On Replacement Engine 5r***83 | 2 |
| 6V***88 | Nut-Full (1/2-13 Thd); (1/2-13-Thd)(Full) | 8 |
244-0121 Filter Gp-Oil
| 13***29 | Seal-O-Ring | 1 |
| 1R***09 | Filter Element-Oil; (Ultra High Efficiency)(Power Train) | 1 |
| 24***21 | Filter Group-Oil; -Transmission | 1 |
269-8135 Housing Gp-Torque Converter
| 03***60 | Ring-Retaining | 1 |
| 09***29 | Ring; (Retaining) | 1 |
| 09***95 | Dowel | 1 |
304-3366 Lines Gp-Power Take-Off
| 06***61 | Seal-O-Ring (Id=40.87mm) | 2 |
| 0T***72 | Bolt; 7/16" Diameter X 1 1/2" Length Generator To Engine | 8 |
| 0V***75 | Screw,Cap,Hexagon H Shaft Mtg,Accessory Drive | 4 |
269-8133 Planetary Gp-Transmission
| 09***45 | Seal | 1 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 9 |
| 0S***90 | Bolt; (3/8-16x2in)(Clip Thru Spacer To Bracket As) | 7 |
269-8142 Pump Gp-Gear -Transmission
| 0S***95 | Bolt 1.25 In. (31.75 mm) Long Guard Assemblies To Radiator Guard | 2 |
| 1H***27 | Seal 10.1 cm(3.984 In.) I.D. | 1 |
| 26***42 | Pump Group-Gear; -Transmission | 1 |
269-8211 Torque Converter Gp
| 06***58 | Ball Bearing | 1 |
| 0S***88 | Bolt,Machine; Hose Assembly Mounting,Hose Assembly To Transmission,And To Torque Converter | 12 |
| 0S***02 | Bolt; (5/8-18x3.5-In) | 3 |
305-8108 Transmission Ar
| 26***33 | Planetary Group-Transmission | 1 |
| 26***34 | Case & Parts Group-Planetary | 1 |
| 26***35 | Housing Group-Torque Converter | 1 |
296-1253 Transmission Ar
| 26***32 | Transmission Ar | 1 |
| 29***76 | Plate & Film Group | 1 |
| 29***53 | Transmission Ar | 1 |
269-8132 Transmission Ar
| 26***32 | Transmission Ar | 1 |
| 26***33 | Planetary Group-Transmission | 1 |
| 26***34 | Case & Parts Group-Planetary | 1 |
300-3751 Transmission Ar
| 12***05 | Adapter | 1 |
| 29***76 | Plate & Film Group | 1 |
| 29***15 | Flywheel Group | 1 |
258-8987 Valve Gp-Modulating
| 16***08 | Washer; (13.03x25.4x2.38-mm Thk) | 1 |
| 16***24 | Nut-Self-Locking; (1/2-28-Thd) | 1 |
| 22***22 | Coil As-Solenoid; (24-Volt) | 1 |
244-3114 Valve Gp-Modulating
| 16***08 | Washer; (13.03x25.4x2.38-mm Thk) | 1 |
| 16***24 | Nut-Self-Locking; (1/2-28-Thd) | 1 |
| 24***14 | Valve Group-Modulating; -Transmission Hydraulic Control | 1 |
126-7174 Valve Gp-Relief
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 4 |
| 12***74 | Valve Group-Relief; -Torque Converter Inlet | 1 |
| 16***67 | Fitting As; (Quick Disconnect, Male)(Quick Disconnect) | 1 |
306-6396 Valve Gp-Relief
| 0S***94 | Bolt (1 In. Long 3/8 In. Dia.); Plate Assembly To Support Assembly | 4 |
| 16***67 | Fitting As; (Quick Disconnect, Male)(Quick Disconnect) | 1 |
| 1L***62 | Ring-Retaining | 1 |
308-2995 Valve Gp-Relief
| 14***25 | Connector As. | 1 |
| 16***77 | Plug As | 1 |
| 1M***51 | Spring-Steering Clutch | 1 |
Service Equipment And Supplies
296-0676 Plate & Film Gp
| 22***81 | Film-Warning; -Universal | 1 |
| 29***76 | Plate & Film Group | 1 |
| 7E***81 | Plate-Identification; (Caterpillar)(New Tm) | 1 |
TH55-E70 serial number reference
The TH55-E70 is sold as a bare petroleum transmission/powertrain package, not a cabbed machine, so its ID plate is riveted to the transmission housing near the input or output flange rather than a cab frame. The plate shows a 3-letter prefix followed by a sequential serial number (for example PCJ00001), where the prefix marks the production series/serial break and the digits are the running unit count within that series.
| Prefix | Identifies | Notes |
|---|---|---|
| PCJ | TH55-E70 Petroleum Transmission — current/standard production prefix | Serial range PCJ00001-UP. Covers the TH55-E70 petroleum transmission and the TH55-E70-3512CP petroleum powertrain package (engine arrangement plus transmission). Fits Cat 3512C (HD) and 3516C (HD), Cummins QSK50 and QSK60, and MTU 12V4000 and 16V4000 engines for well-service pressure-pumping duty. Seven forward speeds, no reverse, deep first-gear ratio near 6.25:1, integral torque converter (stall ratio about 2.23). Gross input power up to roughly 2461 kW (3300 hp). Predecessor to the later 9-speed TH55-E90. |
| THE | TH55-E70 Petroleum Transmission — earlier serial-range prefix | Appears repeatedly in the transmission arrangement parts breakdown as a paired range with PCJ (listed as "THE1-UP; PCJ1-UP") across pump, coupling, flywheel adapter, and oil-line groups for the TH55-E70 transmission assembly. Represents an earlier production serial break carried in the same parts manual as the PCJ range, same driveline scope as PCJ. |
| JW7 | TH55-E70 Petroleum Transmission — limited early-production serial range | Confirm with dealer. Single listing found: S/N range JW71-197 tied to the torque converter group within the TH55-E70 transmission arrangement breakdown. Very short range (about 197 units), consistent with an early or transitional production block predating the THE/PCJ ranges. Only one source located for this prefix. |
Frequently asked questions
What engine powers the Cat TH55-E70?
None built in. The TH55-E70 is a stand-alone transmission, not a complete power package. It bolts to a customer-selected engine, such as Cat 3512C HD, 3516C HD, or 3516D HD, or a Cummins QSK50/QSK60, or an MTU 12V4000/16V4000, through an SAE C/J744 pump drive and an SAE #0 flywheel input.
What is the operating weight of the TH55-E70?
Cat does not publish a standalone operating weight for the TH55-E70. As a mining-truck-derived powershift transmission built to handle input power up to roughly 3300 hp, it is a heavy standalone driveline component, sized to its engine and pump-drive pairing rather than quoted as a simple accessory-transmission weight figure.
What replaced the Cat TH55-E70?
Nothing has replaced it; the TH55-E70 remains in current Cat production. Its closest relative is the TH55-E90, a nine-speed forward, no-reverse version of the same transmission built for tighter gear steps through the working pump range. Cat Reman even allows a TH55-E70 core to be exchanged for a TH55-E90 unit.
What TH55-E70 owners discuss
How does the TH55-E70 actually engage gears, and is there anything unusual operators should know before running one?
Why do some fleets spec the 7-speed E70 with its deep first gear instead of the 9-speed E90, and does that affect wear?
Does the transmission behave differently depending on which engine it is paired with?
What electrical or sensor issues come up most often in the field?
What wear patterns are typical for this transmission in pressure-pumping duty, and how long does it really last?
Why would an operator disable the torque converter lock-up clutch mid-job, and what do the other safety features do?
What should a buyer check on a used TH55-E70 before purchasing it?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Need a specific TH55-E70 part?
Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.