Model Spotlight

Case 550H LT Crawler Dozer: Specs, Parts & Common Issues

Produced 2001 - 2010, the Case 550H LT is the Long-Track variant of the H-generation 550 dozer - Cummins 4T-390 turbocharged diesel, hydrostatic dual-path drivetrain, longer track frame for improved flotation and stability on soft ground. Approximately 90 horsepower, JJG-prefix serial numbers, and a substantially more refined operator station than the G-generation predecessor. The H-generation introduced hydrostatic transmission to the 550-class, replacing the earlier power shuttle architecture.

BT

Broken Tractor Editorial Team• Updated May 2026• 10 min read

The Case 550H LT Crawler Dozer is the Long-Track variant of Case’s H-generation mid-class dozer, produced from approximately 2001 through 2010. The “LT” designation refers to the extended-length track frame - wider track stance and longer ground contact patch compared to the standard 550H, designed for improved flotation on soft ground (wetlands work, agricultural site prep, forestry applications) and increased stability during dozing operations. The 550H LT runs the Cummins 4T-390 turbocharged four-cylinder diesel - the same turbo engine offered as an option on the 550G but now standardized as the 550H base engine.

The H generation introduced a major drivetrain change to the 550 line: the hydrostatic transmission replaced the earlier power shuttle architecture used on the 550 through 550G. Each track has its own hydraulic motor and pump - direction and speed are controlled by joystick rather than by shifting gears and reversing direction with a clutch. The hydrostatic drivetrain is a substantial change in operator experience and in parts service: hydrostatic motors, pumps, and control valves are the new wear items.

At-a-glance specifications

How the 550H differs from the 550G

The 550H is a substantial platform refresh over the 550G:

• Hydrostatic transmission replaces power shuttle - the most significant drivetrain change. Each track has its own hydraulic motor driven by a variable-displacement pump. Operator controls direction and speed via joystick rather than gear shifting. Smoother control, more responsive direction changes, but new service items (hydrostatic motors, pumps, charge pumps).
• Cummins 4T-390 standardized - the 550G offered NA or turbo as an order option; the 550H standardizes on the 4T-390 turbo across all configurations.
• Refined cab and electronics - H-generation cab is more refined with improved HVAC, electronic gauge cluster, and updated controls.
• Updated undercarriage - several track and roller components updated, though many cross-fit with the 550G via the R57298 sprocket, R58450 chrome adjuster rod, and R57366 master pin.

Long-Track (LT) variant

The 550H LT differs from the standard 550H primarily in the track frame:

• Longer track frame - extended-length track gives more ground contact area, improving flotation on soft ground and stability during dozing.
• Wider track pads typically - LT machines often ship with wider grouser pads for additional flotation. The 305440A1 cutting edge end is explicitly labeled for 550H LGP variants - confirm track configuration before ordering blade hardware.
• Same engine and drivetrain as standard 550H - the Cummins 4T-390 and hydrostatic transmission are unchanged from the standard 550H.

Cummins 4T-390 turbocharged engine

The 4T-390 is the turbocharged variant of the Cummins 4BT 3.9L industrial four-cylinder family. Same 239 cubic inch displacement and bore-stroke geometry as the 4B-390 (which was the NA option on the 550G), with the addition of a wastegated turbocharger and heavier-duty internal components designed to handle the boosted intake.

Engine internals source readily through the broader Cummins B-series parts ecosystem. The CS-550H-T-FK turbo filter kit is the 550H-specific filter set for the Cummins 4T-390. For the engine fan belt, the J903098 engine fan belt covers 450C through 550H dozers (and certain Case XT-series skid steers).

Hydrostatic transmission

The hydrostatic dual-path transmission is the biggest service difference from earlier 550-series dozers. Each track has its own hydraulic motor; flow to each motor is controlled by a variable-displacement pump and joystick-operated control valve. The result is smooth, infinitely-variable speed control and clutch-free direction changes - but with hydrostatic service points that the earlier power-shuttle machines didn’t have.

Common hydrostatic service items: charge pump wear, control valve degradation, hydraulic motor seal failure, and hydraulic oil contamination from internal wear. Hydrostatic-system service generally requires dealer service tools for diagnosis and pressure testing.

Undercarriage

The 550H LT undercarriage shares its sprocket with the broader 550 family - the R57298 long-track sprocket cross-fits 550 (post-JAK0013968), 550E, 550G, and 550H. Track adjustment uses the same chrome-rod system: R58450 chrome rod and R58480 complete assembly.

For wear-strip and idler service, the 144392A3 track idler wear strip replacement kit covers 450 through 550H - extremely broad cross-fit. The D35276 3/8” thick wear plate and PV432 1/2” thick wear plate are both labeled for 310 through 550H.

For slider blocks and wear plates on the blade carrier, the 117835A1 slider block covers 550H, 650G, 650H, 750H, 850G, and 850H - broad cross-fit across multiple H-generation machines. The 117836A1 wear plate shares the same cross-fit.

Blade system

The 550H standard blade is 96 inches wide. The CS-550H-CEK cutting edge kit covers the complete cutting edge replacement including bolts and nuts. For individual cutting edge pieces, the 311729A1 center cutting edge handles the center section and the 305440A1 cutting edge end handles the end sections (also fits 550H LGP).

For blade hydraulic service, the CS-550H-SKD blade hydraulic cylinder seal kit package is the 550H-specific blade seal package. Individual blade cylinders: the 307662A1R rebuilt blade angle cylinder is the verified angle cylinder, and the 310478A1 angle cylinder seal kit (1¾” rod, 3” bore) covers angle cylinder rebuild.

Hydraulic pump

The 360677A1 hydraulic pump is the 550H-specific main hydraulic pump (new OEM). This is the implement-circuit pump for blade and ripper functions, separate from the hydrostatic drive pumps.

Operator station

The 359121A1 Case / New Holland dozer suspension seat with headrest is the verified seat replacement - broad cross-fit covering 550H, 650H, 650K, 650L, 750K, 750L, 850H, 850K, 850L, and more.

Parts we carry

The parts table below covers the top routine-service and cross-fit parts for this model.

For a comprehensive Case 550H / 550H LT parts inventory, browse the Case Dozer Parts hub.

Common issues and what to expect

Hydrostatic transmission service

The hydrostatic dual-path drivetrain introduces new service items not present on earlier 550-series dozers. Charge pump wear, control valve degradation, hydraulic motor seal failure, and hydraulic oil contamination are routine. Hydrostatic diagnosis usually requires dealer service tools.

Turbocharger wear

The Cummins 4T-390 turbocharger is a routine wear item on 15-plus-year-old engines. Symptoms: blue smoke at startup, oil consumption, audible whine outside the normal range, or visible shaft play. Replace at the first sign of bearing wear.

Blade carrier wear plate replacement

The 117835A1 slider block and 117836A1 wear plate are routine blade-carrier service items - both have broad H-generation cross-fit and wear with normal blade angle/tilt operation.

Blade cylinder seal failure

The CS-550H-SKD seal kit package covers the 550H-specific blade cylinder rebuild. For individual cylinder service, the 310478A1 angle cylinder seal kit handles the angle cylinder rebuild.

Cutting edge wear

The CS-550H-CEK cutting edge kit covers the complete 96-inch blade cutting edge with hardware. Replace when the cutting edge wears thin or the blade starts losing depth control.

Undercarriage wear

The LT (Long-Track) configuration sees particular wear on idler bushings and roller bearings due to the extended track frame. The 144392A3 idler wear strip kit covers the wear strip replacement.

Filter service

Use the CS-550H-T-FK turbo filter kit at scheduled intervals - engine oil, fuel, air, hydraulic filters for the Cummins 4T-390 engine.

Seat replacement

The 359121A1 suspension seat with headrest is the verified seat replacement when the original cushion or suspension fails.

Where the 550H LT sits in the Case dozer family

The 550H LT is the Long-Track variant of the H-generation mid-class Case crawler dozer. Above it sits the 650H family; below it sits the Case 450C. Before the 550H came the 550G (power shuttle drivetrain, two engine options). The H-generation introduced hydrostatic dual-path transmission to the 550 line - a major drivetrain change that defines this generation’s service profile.