DIFFERENTIALS
28 results
48 Items
Sort by:
Best selling
Extensive industry knowledge available when you need it.
Contact us today for expert assistance sourcing your part.
Differential Parts For Peterbilt Trucks
The differential is the final link in the Peterbilt drivetrain, splitting torque between the drive wheels while allowing them to rotate at different speeds through corners. On tandem-axle Peterbilts, an inter-axle differential (power divider) also manages torque distribution between the forward and rear drive axles. Differential components — including ring and pinion gears, bearings, seals, carriers, and locking mechanisms — must withstand extreme torque loads and heat, making proper maintenance and timely repair essential for preventing catastrophic drivetrain failure.
Frequently asked questions about differentials
What are signs that a Peterbilt differential needs service?
Common indicators of differential problems on a Peterbilt include a howling or whining noise from the rear axle area that changes with vehicle speed, vibration during acceleration or deceleration, clunking when engaging or releasing the inter-axle differential lock, or gear oil leaks at the axle housing or carrier gasket. Overheating differentials — detectable by a burning gear oil smell — are also a warning sign, often caused by low fluid level, incorrect lubricant viscosity, or failed bearings causing excess friction.
How often should differential gear oil be changed on a Peterbilt?
Meritor, Dana Spicer, and other major axle manufacturers typically recommend a first oil change at 5,000 miles on a new or rebuilt differential to flush break-in metal particles, followed by changes at 25,000 miles or annually under normal conditions. Extended drain intervals up to 500,000 miles are possible with synthetic gear lubricants that meet the manufacturer's specifications, provided oil analysis confirms the lubricant is still within spec. Always consult your axle manufacturer's service manual for the correct lubricant grade and interval for your specific axle model.
What is a limited-slip or locking differential, and when is it used on Peterbilt trucks?
Standard open differentials allow all torque to flow to the wheel with the least resistance — useful on pavement, but ineffective when one wheel loses traction. Locking differentials (driver-selectable via a dash switch on most Peterbilts) mechanically lock both axle shafts together, forcing equal wheel rotation and maximizing traction in off-road, loose surface, or slippery conditions. Locking diffs should only be engaged at low speeds and disengaged on pavement, as locked axles on dry roads cause driveline binding and accelerated tire and gear wear.