How to measure for a driveshaft

Single drive-shaft application
Slide the trans yoke all the way into the transmission, then back it out one inch. Measure from the center of the u-joint hole in the trans yoke to the center of the u-joint hole in the pinion yoke on the differential. This will give you the over-all length of the drive shaft. (Rear axle must be supported or tires must be on the ground.)

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Two-piece Driveshaft
The two-piece driveshaft is most commonly found in full size pick up trucks, utility trucks, RVs, and some late model automobiles. The overall distance between the transmission and the differential is more than the recommended driveshaft length, so a carrier bearing (sometimes referred to as a mid-shift bearing) is used between the two points to support the driveshaft.

The procedure for measuring a two-piece driveshaft is similar to that in Diagram A. Lift the vehicle by jacking up the front end and the rear axle, to ensure proper ride height and angle. Slide the trans yoke into the transmission until it stops. Back it out 1”, then measure from the center of the u-joint hole in the trans yoke to the center of the carrier bearing (as shown in Diagram B). This is length # 1. Now measure from the center of the carrier bearing to the center of the u-joint hole in the rear yoke. This is length #2. Refer to Diagram D to determine the series of your driveshaft, which will also help to determine which carrier bearing is used in your application. (Rear axle must be supported or tires must be on the ground.)

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