Caterpillar PR-450
Maintenance schedule, common problems & OEM parts breakdown
The Caterpillar PR-450 is a self-propelled, three-track cold planer built for asphalt and concrete milling, produced under the 1985 manufacturing agreement between Caterpillar and CMI Corporation that put the Cat badge on CMI-built paving equipment. It carries the Cat 3408 DITA, a mechanically governed V8 diesel rated around 450.6 hp (336 kW) with no electronic engine control. Operating weight runs approximately 25,760 kg (56,791 lb), with a cutting width of 1.92 m (6.3 ft) and maximum cutting depth of 254 mm (10 in). It has no direct Cat predecessor, since it was part of Caterpillar's first cold-planer lineup alongside the PR-75, PR-105, PR-275, and PR-750B, all rebadged CMI Roto-Mill designs. Fuel capacity is around 757 L (200 gal), and the machine was offered as a single three-track chassis configuration built around the fixed-width cutting head.
Across its production life the PR-450 stayed close to its CMI engineering roots: a mechanically governed 3408 diesel, hydrostatic-hydraulic drive, and a three-track chassis with no electronic controls to fail. Caterpillar eventually replaced it with the later PR-450C generation, which moved to updated machine controls documented in its own factory manual; specifics of that generation belong to its own service literature, not this one. In today's used and parts market the PR-450 matters because its all-mechanical drivetrain is straightforward to keep running and rebuild without diagnostic tooling, making it a value option for contractors running older milling fleets. Factory support for this CMI-era generation has thinned over time, so cutting-drum, conveyor, and undercarriage components are increasingly sourced through salvage and aftermarket channels rather than new-parts counters.
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 PR-450 specifications
Engine
| Engine model | Cat 3408, V8 four-stroke diesel (7DC-prefix production; factory service literature also references a later PR-450C revision, specs not independently confirmed) |
| Gross power | 336 kW (450.6 hp) |
| Net power | Not documented in available spec sources |
| Displacement | 18.0 L (1,098.5 cu in) |
| Cylinders | 8 (V8 configuration) |
| Emissions tier | Not documented — mechanical diesel predating modern emissions-tier regulation, no tier rating published |
Weights
| Operating weight (full load) | 25,760 kg (56,791 lb) |
| Shipping weight | Not documented separately from operating weight |
| Ground pressure | Not published |
Dimensions
| Overall (operating) length | 13.29-13.30 m (43.6 ft) |
| Shipping width | 2.87-2.90 m (9.4-9.5 ft) — minor variance between sources |
| Shipping height | 4.27 m (14 ft) |
| Track width (front and rear, each) | 30.7 cm (12.1 in); 3 track units total |
| Discharge conveyor width | 76.2 cm (30 in) |
| Cutting (milling) width | 1.92 m (6.3 ft) |
| Maximum cutting depth | 254 mm (10 in) |
| Wheelbase / track gauge | Not documented |
| Ground clearance | Not documented |
Performance
| Milling (operating) speed | Up to 53.6 m/min (175.9 ft/min) |
| Travel speed | 3.2 km/h (2 mph) |
| Gradeability | Not published |
Service capacities (summary)
| Fuel tank | 757.4 L (200.1 gal) |
| Water spray (dust suppression) tank | 2,649.9 L (700.1 gal) — separate from hydraulic system |
| Hydraulic system | Not documented in available spec sources |
| Engine oil | Not documented in available spec sources |
| Cooling system | Not documented in available spec sources |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
PR-450 fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) — Cat 3408 diesel | approx. 46-76 L (12.2-20.0 US gal), varies by oil pan and dual-filter configuration; exact figure for this chassis mounting not confirmed | Cat Diesel Engine Oil (DEO) SAE 15W-40 or equivalent meeting API CD/CE/CF-4; drop to a lighter-grade DEO or Cat DEO Cold Weather oil for sub-zero starts per the cold-weather viscosity chart |
| Cooling system | approx. 113.6 L (30.0 US gal) full system including radiator; generic figure for the 3408 industrial engine family, not confirmed specific to this machine's radiator/plumbing | conventional Cat heavy-duty antifreeze/coolant (this model line predates Cat ELC) mixed 50/50 with water and dosed with Supplemental Coolant Additive (SCA) at every service interval; raise the antifreeze ratio for extreme-cold climates, never exceed max concentration |
| Fuel tank | 757 L (200 US gal) | No. 2-D diesel fuel; switch to No. 1-D or a winter-blend diesel below freezing to avoid fuel waxing and filter plugging |
| Water spray system (cutting-drum/dust-suppression tank, separate from engine cooling) | 2650 L (700 US gal) | clean water for the spray-bar and drum-cooling circuit; drain and blow out lines ahead of freezing weather to prevent pump and line damage |
| Hydraulic system and tank (propel, cutter-drum, and conveyor circuits) | not documented in available sources for this exact model/serial range — verify tank capacity with your dealer or the machine's own OMM | Cat TDTO-type multipurpose tractor hydraulic oil (SAE 10W), typical of this era's combined hydraulic/powertrain circuits; Cat TDTO Cold Weather or Arctic-grade oil for sub-zero startup |
| Track final drives (each side) | not documented in available sources for this exact model/serial range | Cat TDTO gear oil (SAE 10W/30W selected by ambient temperature) or equivalent GO-spec gear oil for the final-drive/track-drive gear cases |
| Grease (spec only) | N/A — applied at grease fittings per the OMM lubrication schedule | Cat Multipurpose Grease (moly EP, NLGI 2) for pins, bushings, and cutter-drum bearing points; Cat Arctic Platinum grease for extreme-cold service |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Caterpillar PR-450 maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
Servicing the PR-450 beyond the schedule
Predictive Maintenance & Fluid Analysis
The 3408 DITA on the PR-450 is mechanically governed with no ECM, so there is no onboard fault logging to lean on. Build a trend file from oil sampling instead: watch for rising iron and copper that flag turbocharger or bearing wear, and check coolant samples for the cavitation and liner pitting common to this wet-liner V8. Because the drum's water spray system runs near the hydraulic bay, sample hydraulic oil periodically for water intrusion from spray-line leaks before it degrades pump seals.
Corrective & Common Repairs
Expect cutting drum bearing and seal failures from milling grit working past worn seals, plus recurring water spray nozzle clogging that lets teeth run hot and wear unevenly. Track tension adjusters on the three-track undercarriage are a common leak point and should be checked whenever ground speed feels inconsistent. Conveyor belt misalignment and tears from tramp debris are routine repairs, and mechanical injector pump adjustment is the usual fix for uneven cylinder performance on this governed 3408.
Overhaul & Rebuild Points
Major rebuild points on the PR-450 center on the 3408 DITA inframe overhaul once oil analysis and compression trends show it, paired with turbocharger rebuild at similar hours. The cutting drum reduction gearbox and drum bearings wear from continuous abrasive contact and are a standard high-hour rebuild. All three track chains, rollers, and idlers should be evaluated together, since uneven track wear on this chassis accelerates once one track falls behind the others.
Seasonal & Environment Servicing
In cold weather, verify coolant concentration protects the 3408's wet cylinder liners from cavitation and use a block heater to ease cold starts on this mechanically governed engine; watch fuel for gelling in low temperatures. In hot, dusty milling environments, keep the water spray system fully serviced since it does double duty cooling teeth and suppressing dust, and shorten air filter service intervals. Drain the fuel-water separator more frequently in humid or wet-season conditions.
PR-450 fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| High Coolant Temperature (warning lamp) | Engine coolant temperature above normal operating range | Low coolant level, blocked radiator core, slipping or failed fan drive, faulty coolant temperature sender | Idle down and stop, let engine cool, check coolant level and radiator fins for debris, verify fan drive engagement before restart |
| Low Engine Oil Pressure (warning lamp) | Oil pressure sender reads below the safe threshold | Low oil level, plugged oil filter, worn oil pump or bearings, faulty pressure sender | Shut engine down immediately, check oil level and filter condition, confirm sender wiring before restart |
| High Hydraulic Oil Temperature (warning lamp) | Hydraulic tank temperature above normal range | Low hydraulic fluid level, clogged hydraulic oil cooler core, stuck relief valve, cooling fan drive fault | Idle down to cool, check fluid level, inspect cooler core for packed debris, verify fan operation |
| Air Filter Restriction (service indicator) | Intake air filter restriction indicator shows excessive vacuum | Clogged primary or secondary air filter element, collapsed intake hose | Inspect and replace air filter elements, reset the restriction indicator, check intake piping for leaks or collapse |
| Low Battery / Charging Voltage (warning lamp) | Charging system voltage below normal system voltage | Loose or worn alternator belt, faulty alternator or regulator, corroded battery or wiring connections | Check belt tension and condition, test alternator output, inspect battery terminals and grounds |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
PR-450 attachments & work tools
Cutting drum / rotor
Fixed cutting width of about 1.92 m (6 ft 3 in) with a maximum cutting depth of about 254 mm (10 in). The rotor is a single full-width unit, not an interchangeable carrier attachment, and the width/depth figures are consistent across spec sources for this model.
Cutting tools (bits) and holders
The drum carries individually replaceable cutting tools set in mechanical holders around its circumference, standard practice for this class of self-propelled planer. Exact bit style and holder part families are not confirmed in available documentation specific to this model; verify current tool and holder spec with a dealer before ordering.
Discharge conveyor
Single discharge conveyor, about 762 mm (30 in) wide, carries milled material from the cutting chamber to a truck or windrow. No secondary/folding conveyor or width variant is documented for this model.
Water spray / dust suppression system
Integrated water spray system for cutting-chamber dust and temperature control, with an onboard tank capacity in the range of about 2,650 L (700 gal). This is a built-in machine system rather than a bolt-on option kit for this model.
Undercarriage / propulsion configuration
Three-track undercarriage arrangement (not wheeled) with rubber track pads roughly 300 mm (12 in) wide front and rear, giving the machine its low ground-bearing footprint for grade control while milling.
Guarding and factory width/option variants
No verified factory guarding packages, alternate drum-width options, or half-lane configuration is documented specifically for this model in available sources. Later Cat half-lane and heavy-duty cold planer lines are separate model families and should not be assumed to apply here; confirm any option variant with a dealer.
All PR-450 assemblies by section
Every catalogued assembly group for the Caterpillar PR-450. Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Pavement Profiler
503584 Air And Exhaust Assembly
| 50***84 | Air And Exhaust Assembly | 1 |
5035060 Air System Assembly
| 50***60 | Air System Assembly | 1 |
5034014 Attachment : Conveyor Swing Remote
| 50***14 | Attachment: Conveyor Swing Remote | 1 |
5034003 Attachment : High Press Water System
| 50***03 | Attachment: High Press Water System | 1 |
5034001 Attachment : Slope Control
| 50***01 | Attachment: Slope Control | 1 |
5034018 Attachment : Slope Control
| 50***18 | Attachment: Slope Control | 1 |
5034017 Attachment : Slope Control Right Or Left Leg
| 50***17 | Attachment: Slope Control Right Or Left Leg | 1 |
5034019 Attachment : Slope Control Right Or Left Leg
| 50***19 | Attachment: Slope Control Right Or Left Leg | 1 |
5035075 Auxiliary Return Hydraulic System
| 50***75 | Auxiliary Return Hydraulic System | 1 |
5035073 Auxiliary Return System
| 50***73 | Auxiliary Return System | 1 |
5035072 Auxiliary Supply Hyd. System
| 50***72 | Auxiliary Supply Hydraulic. System | 1 |
5035079 Auxiliary Supply Hydraulic System
| 50***79 | Auxiliary Supply Hydraulic System | 1 |
43429 Clutch Assembly
| 4***9 | Clutch Assembly | 1 |
Cmi Roto-Mill Cutting Teeth
503763 Console Assembly
| 50***63 | Console Assembly | 1 |
503737 Console Assembly
| 50***37 | Console Assembly | 1 |
503747 Console Electrical Panel Assy.
| 50***47 | Console Electrical Panel Assembly. | 1 |
5035048 Conveyor & Brake Control Hyd. System
| 50***48 | Conveyor & Brake Control Hydraulic. System | 1 |
5035070 Conveyor Swing & Elevation Hyd. System
| 50***70 | Conveyor Swing & Elevation Hydraulic. System | 1 |
5035034 Conveyor Swing & Elevation Hyd. System
| 50***34 | Conveyor Swing & Elevation Hydraulic. System | 1 |
5035027 Conveyors Drive Hyd. System
| 50***27 | Conveyors Drive Hydraulic. System | 1 |
5035071 Conveyors Drive Hydraulic System
| 50***71 | Conveyors Drive Hydraulic System | 1 |
503476 Cutter Assembly
| 50***76 | Cutter Assembly | 1 |
503702 Decals Assembly, Pr-450
| 50***02 | Decals Assembly, Pr-450 | 1 |
5039001 Electrical Assembly
| 50***01 | Electrical Assembly | 1 |
503746 Electrical Panel Assembly
| 50***46 | Electrical Panel Assembly | 1 |
503826 Elevation Control Support Assy.
| 50***26 | Elevation Control Support Assembly. | 1 |
5035074 Elevation Hyd. System
| 50***74 | Elevation Hydraulic. System | 1 |
503234 Engine Cowling Insulation Assembly
| 50***34 | Engine Cowling Insulation Assembly | 1 |
503592 Fuel System Assembly
| 50***92 | Fuel System Assembly | 1 |
503266 Fuel Tank Assembly
| 50***66 | Fuel Tank Assembly | 1 |
503226 Fuel Tank Assembly
| 50***26 | Fuel Tank Assembly | 1 |
413518 Gear Box Assembly
| 41***18 | Gear Box Assembly | 1 |
503503 Gearbox And Pumps Assembly
| 50***03 | Gearbox And Pumps Assembly | 1 |
5035026 Ground Drive Hydraulic System
| 50***26 | Ground Drive Hydraulic System | 1 |
503227 Hydraulic Oil Tank Assembly
| 50***27 | Hydraulic Oil Tank Assembly | 1 |
503301 Leg Assemblies
| 50***01 | Leg Assemblies | 1 |
5032002 Lower Conveyor Assembly
| 50***02 | Lower Conveyor Assembly | 1 |
5032090 Lower Conveyor Assy.
| 50***90 | Lower Conveyor Assembly. | 1 |
503201 Mainframe Assembly
| 50***01 | Mainframe Assembly | 1 |
578016 Pendulum Assembly
| 57***16 | Pendulum Assembly | 1 |
5035082 Pendulum Assembly (Complete)
| 50***82 | Pendulum Assembly (Complete) | 1 |
503583 Power Pack Assy.
| 50***83 | Power Pack Assembly. | 1 |
Pr-450 Pavement Profiler
5035029 Return Hydraulic System
| 50***29 | Return Hydraulic System | 1 |
5035080 Steering & Moldboard Hyd. System
| 50***80 | Steering & Moldboard Hydraulic. System | 1 |
5035033 Steering & Moldboard Hyd. System
| 50***33 | Steering & Moldboard Hydraulic. System | 1 |
413512 Torque Hub, 53.58 : 1
| 41***12 | Torque Hub 53.58:1 | 1 |
503601 Track Assemblies -- Complete Machine
| 50***01 | Track Assemblies -- Complete Machine | 1 |
503605 Track Frame Assembly -- L.H.
| 50***05 | Track Frame Assembly -- L.H.; Track Frame Assembly -- R.H. | 1 |
5032104 Upper Conveyor Assembly
| 50***04 | Upper Conveyor Assembly | 1 |
5032070 Upper Conveyor Assembly
| 50***70 | Upper Conveyor Assembly | 1 |
5032069 Upper Conveyor Cover Assembly
| 50***69 | Upper Conveyor Cover Assembly | 1 |
5032112 Upper Conveyor Support
| 50***12 | Upper Conveyor Support | 1 |
5032004 Upper Conveyor Support Assembly
| 50***04 | Upper Conveyor Support Assembly | 1 |
5031001 Water Spray Bar System
| 50***01 | Water Spray Bar System | 1 |
503228 Water Tank Assembly
| 50***28 | Water Tank Assembly | 1 |
503818 Wheel Mount Assembly
| 50***18 | Wheel Mount Assembly | 1 |
PR-450 serial number reference
The PIN/serial plate is a stamped metal tag riveted to the main frame, generally on the operator's-platform side of the machine; a separate engine-data plate sits on the engine near the injection pump or rocker cover. Read the first 3 characters of the PIN as the prefix (identifies the model/build series) and the remaining digits as the sequential unit number within that series. If the plate is worn, cross-check the number stamped on the frame rail near the plate location.
| Prefix | Identifies | Notes |
|---|---|---|
| 7DC | PR-450 cold planer, base/only production series | Only documented prefix for the PR-450 (the later PR-450C carries its own separate prefix, 7PJ, and is a distinct successor line). Fitted with the Cat 3408 V8 diesel, turbocharged-aftercooled (DITA) rating, 450.6 hp (336 kW), 18.0L displacement, 137mm bore x 165mm stroke. Parts documentation shows an engine-arrangement break within the same 7DC prefix around unit 7DC00204-up; region/plant of manufacture not confirmed from available sources. |
Frequently asked questions
What engine powers the Caterpillar PR-450 cold planer?
A Caterpillar 3408 DITA V8 diesel, rated around 450.6 hp (336 kW). It is mechanically governed with no electronic engine control.
What is the operating weight of the Caterpillar PR-450?
Approximately 25,760 kg (56,791 lb). Exact figures vary slightly by configuration and source.
What replaced the Caterpillar PR-450?
It was succeeded by the later PR-450C generation, which is documented under its own separate factory manual.
What PR-450 owners discuss
What's the powertrain layout on the PR-450, and how does it behave day to day?
What engine quirks come up most with the 3408 in a PR-450?
What undercarriage and track wear pattern should owners expect on this machine type?
What causes cutting-drum driveline seal failures, and how much wear is normal on the picks?
What electrical or sensor issues show up on machines from this era?
What hydraulic problems come up most, and what's usually behind them?
What should a buyer check on a used PR-450 before purchase?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
Need a specific PR-450 part?
Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.