Peterbilt 379 Drivetrain Parts

Frequently Asked Questions About Peterbilt 379 Drivetrain Parts

What years of Peterbilt 379 are compatible with your drivetrain parts?

Our drivetrain parts are designed to fit Peterbilt 379 models from 1987 through 2007. However, compatibility can vary depending on your specific engine and transmission configuration. For example, parts for Cat 3406E engines differ from those for Cummins N14 or ISX setups. We recommend checking your OEM or calling our tech support at (417) 624-1010 with your truck's specifications to ensure proper fitment.

How difficult is it to replace U-joints and carrier bearings on a 379?

Replacing U-joints typically requires 2-4 hours for an experienced mechanic and basic hand tools including a U-joint press or large vise. Carrier bearing replacement is more involved, requiring the driveshaft to be removed and often needing a hydraulic press. Many customers report that having the correct measurements beforehand saves significant time. Alignment must be checked after installation to prevent vibration issues.

What's the difference between standard and heavy-duty driveshaft components?

Standard components are rated for typical highway applications up to 80,000 lbs GVW, while heavy-duty options are engineered for vocational use, heavy hauling, or trucks exceeding 80,000 lbs. Heavy-duty U-joints feature thicker cross sections and upgraded needle bearings, while HD carrier bearings use sealed designs with higher load ratings. If you're running oversize loads or in severe service conditions, the heavy-duty upgrade typically doubles component life.

Do you carry parts for both manual and automatic transmission setups?

Yes, we stock drivetrain components for all factory transmission options including Eaton Fuller 13 and 18-speeds, as well as Allison automatic applications. The main differences are in yoke styles and driveshaft lengths. Manual transmission trucks typically use different slip yoke designs than automatics. When ordering, you'll need to know your transmission model number, which is stamped on the transmission tag.

What causes driveline vibration and which parts should I check first?

Driveline vibration in 379s commonly stems from worn U-joints, failing carrier bearings, or improper driveshaft angle. Start by checking U-joint play - any movement indicates replacement is needed. Carrier bearings often show wear through rubber deterioration or bearing noise. We recommend replacing U-joints in pairs and checking driveshaft balance if vibration persists after component replacement. Proper torque specs and alignment angles are critical for vibration-free operation.