Parts of a Drive Shaft – Labeled Diagram with Names

All 12 parts on the diagram

Show the list

The whole shaft 7

Slip yoke Its barrel slides in and out of the back of the transmission. The shaft can then get a little longer or shorter as the rear axle moves up and down.
Splines They mesh with matching ribs on the transmission's shaft. The two turn together but are free to slide.
Driveshaft tube Hollow, and much stronger than a solid shaft of the same weight. This shaft has two tubes, one each side of the center bearing.
Center support bearing It holds up the middle of a two-piece shaft. Its bracket bolts to the car. A one-piece shaft has none.
Universal joint It lets one shaft drive another at an angle. It keeps driving while the angle changes. This shaft has three. It is also called a U-joint.
Flange yoke It bolts flat against the companion flange.
Companion flange It is on the axle's drive pinion, not on the shaft. The flange yoke bolts to it, and that joins the shaft to the axle.

A universal joint, taken apart 5

Yoke Each universal joint has two, set a quarter turn apart. Each holds two opposite arms of the cross in its two ears.
Cross It links the two yokes. Other names for it are the journal and the spider.
Trunnions Each one turns inside a bearing cap. That is what lets the joint bend.
Bearing caps (cups) Each one holds the bearing a trunnion turns in. It is pressed into an ear of a yoke. Some books call them bearing cups.
Snap rings One clips in beside each bearing cap. It keeps the cap in its yoke.

How this list was compiled: Part names checked on 2026-09-30; a name is kept only when two independent sources use it. (1) US Army TM 9-8000, Principles of Automotive Vehicles, 1985, chapter 28, Propeller Shafts, Slip Joints, and Universal Joints, https://archive.org/details/tm-9-8000-principles-of-automotive-vehicles-1985 (propeller or drive shaft, hollow shafts, slip joint and its splines, slip yoke and sliding yoke, universal joint of one journal and two yokes, bearings where the journal meets the yokes, flange yoke, companion flange, center bearing). (2) T. W. Birch, Manual Drive Trains and Axles, Prentice Hall 1994, searched in full text at https://archive.org/details/manualdrivetrain0000birc (slip yoke, slip joint splines, cross and yoke joint, trunnion, bearing cup, snap ring, flange yoke, tube yoke, companion flange, driveshaft tube, two-piece driveshaft with a center support bearing and three U-joints). (3) J. D. Halderman, Automotive Chassis Systems, Pearson 2017, searched in full text at https://archive.org/details/automotivechassi0000hald (center support bearing of a two-piece driveshaft, bearing caps held on the U-joints by snap rings, trunnion, driveshaft tube, cross). (4) W. H. Crouse, Automotive Mechanics, McGraw-Hill 1980, searched in full text at https://archive.org/details/automotivemechan00crou (slip joint, slip yoke, spider and its trunnions, yokes). (5) Wikipedia, Drive shaft and Universal joint, text only (one-piece and two-piece drive shafts, slip joint, universal joint, a cross with four arms). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's shaft, nothing traced. Licence: own work

How it works

The parts of a driveshaft carry the engine's turning from the transmission back to the rear axle. This one is in two pieces, so it has a bearing in the middle and three universal joints.

Read the full guide

End to end

Start at the left, where the slip yoke's splines slide into the transmission. Then come a universal joint, the front tube, the center support bearing, a second joint, the rear tube and a third joint. The flange yoke at the right end bolts to the companion flange on the rear axle.

Inside a universal joint

Each joint is two yokes and a cross. The cross has four arms called trunnions. A bearing cap fits over each trunnion and presses into a yoke, and a snap ring keeps each cap in place.

A one-piece shaft is simpler: one tube, a universal joint at each end and no center bearing.
The Army's manual calls this a propeller shaft and says either name may be used.

Questions and answers

What are the parts of a drive shaft?

A slip yoke with splines at the transmission end, one or two hollow tubes, a universal joint at each end of each tube, a center support bearing on a two-piece shaft, and a flange yoke that bolts to the rear axle's companion flange.

What does the slip yoke do?

It lets the shaft change length. The rear axle moves as the springs flex, and that pulls and pushes on the shaft. The slip yoke's splines slide in and out to take it up, and still pass on the turning.

What is a universal joint made of?

Two yokes set a quarter turn apart and a cross between them. Each of the cross's four trunnions turns in a bearing cap held in a yoke. That lets one shaft drive another at an angle.

What is the bearing in the middle of a drive shaft called?

The center support bearing, or center bearing. It supports the middle of a two-piece shaft, where the front and rear tubes meet.