Rear Drive Axle/Differential - Dana 80

Rear Drive Axle and Differential

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NOTE: Unless noted, the procedures apply to the conventional differential and Trac-Lok(R) differential, though most of the illustrations used in the procedures show the conventional differential.

The Model 80 rear axle features the following:

- Hypoid-design differential ring gear and pinion with the centerline of the pinion set below the centerline of the differential ring gear
- Full floating axle shafts
- Integral-type differential housing consisting of a cast center section with 2 steel tubes
- Stamped differential housing cover for gasoline engine vehicles
- Cast aluminum finned differential housing cover for diesel engine vehicles
- Conventional differential assembly for F-250
- Conventional differential assembly or a Trac-Lok(R) limited-slip differential assembly for F-350

The rear drive axle and differential receives rotational torque from the driveshaft. The direction of the rotation determines the direction of movement of the vehicle. The torque is relayed through the pinion flange to the drive pinion. The drive pinion rotates the differential ring gear. The ring gear is bolted to the differential flange which is part of the differential case. In the differential case, the pinion shaft has a pinion gear on either end and is pinned in the case. The pinion gears mesh with the differential side gears. The side gears are splined and rotate the axle shafts. It is the side gear and pinion gear relationship inside the differential that allow the drive wheels to turn at different speeds when necessary, such as driving around a corner. A limited slip differential has a pack of plates and friction discs behind the side differential gears to equalize the torque available to each rear wheel when the traction at the rear wheels is not equal.