Driveline System

Driveline System

The source of the drivetrain power is generated by the engine and delivered to the transmission. The driveline transfers the engine torque through the driveshaft to the axle.

- On 2-Wheel Drive (2WD) vehicles, power is transmitted through the transmission to the driveshaft and then to the rear axle.
- On Four-Wheel Drive (4WD) vehicles, power is transmitted through the transmission and the transfer case. The transfer case directs the power to the rear driveshaft and then to the rear axle. When engaged, it also transmits power through the front driveshaft to the front axle.

There are 4 types of driveshafts used:

- One-piece rear driveshaft with 2 U-joints and a front slip yoke.
- Two-piece rear driveshaft with 3 U-joints, a front coupling shaft, a center bearing and a rear slip yoke.
- Three-piece rear driveshaft with 4 U-joints, 2 center bearings and a rear slip yoke.
- One-piece front driveshaft with a single U-joint, a double cardan U-joint and a slip yoke.

The rear driveshaft is connected to the output shaft of the transmission or transfer case and to the rear axle. The front driveshaft is connected to the transfer case and to the front axle. U-joints are used at both ends of the driveshaft to allow for angular motions. Slip yokes are used to allow for any changes to the length of the driveshaft. The engine torque enters the axle through the drive pinion, which rotates the ring gear. The ring gear is mounted to the differential case, which contains the gears that transmit power to the rear axle shafts or front halfshafts. These shafts rotate the drive wheels.



Dana 80 Rear Axle Identification Tag











Ford Rear Axle Identification Tag











Ford Axle Identification Tag Denoting Interchangeability Affected Internally










Dana Front Axle Identification









NOTE: The axle identification tag is the official service identifier. Do not damage the tag. Always reinstall the tag after removing it for axle inspection/repair.

The axle identification tag identifies a particular axle design, a specific ratio and if it is a conventional or limited slip type. In addition, the plant code will not change as long as that particular axle assembly never undergoes an external design change. If, however, an internal design change takes place during the production life of the axle and that internal change affects parts interchangeability, a dash and numerical suffix is added to the plant code. This means that as an assembly both axles are interchangeable; however, internally they are different. Therefore, each requires different internal parts at the time of repair.