A universal joint or u-joint is a cross-shaped casting with short even-length arms, and cups with needle bearings fitted onto the end of each arm. It is packed with heavy grease for lubrication and often has a grease fitting to allow regular servicing. The bearing cups press into machined holes in the driveshaft and component flanges and are usually held in place by clips.
The job of a universal joint is to help transfer power from the engine to the wheels. The most common application is on a rear-wheel drive vehicle, which uses a driveshaft to connect the transmission to the differential. The heights and angles of both of these vary from vehicle to vehicle and depending on how much weight is being carried and how much power is being applied. Because of the varying angles a rigid connection between the two isn’t practical, and a u-joint is used to provide flexibility.
On a simple one-piece driveshaft there is a u-joint at the front where it connects to the transmission, and a u-joint at the back where it connects to the differential. On a two-piece driveshaft another u-joint is added in the middle, along with a carrier bearing that holds the center of the driveshaft steady to the vehicle frame.
Other applications are on a four-wheel-drive vehicle, which has a second driveshaft using u-joints to transfer power from a transfer case to the front differential. Replacement is basically the same in either case; the driveshaft is removed from the vehicle, the holding clips are removed from the u-joint, and the u-joint cups are knocked out of the flanges they are pressed into. Installation is a little tricky, having a particular order in which it needs to be done, and some care is required that the needle bearings stay in place during assembly. But it’s usually quick to work, and not difficult to a mechanic who has done a few and has an understanding of the procedure.
Cost of U-Joint Replacement
On average, it costs about $130 to replace a universal joint on most vehicles. The labor is about the same on most, and parts don’t vary a great deal between different vehicles.
For some specific examples using $100 an hour as a labor rate:
On a 2000 Ford F150, the labor time to replace a rear u-joint is about an hour, which includes removing the driveshaft, replacing the u-joint, and re-installing the driveshaft. Dana is the OE manufacturer, and a new factory u-joint costs about $30. A heavy duty (solid core) Dana u-joint costs about $40. An aftermarket SKP u-joint costs about $20. So the range of costs is from about $120 to about $140, depending on the parts used.
Other trucks, domestic and import, and essentially equivalent. On the Ford example above, with four wheel drive the front driveshaft would follow the same labor costs and parts options if it needed a u-joint replaced.
One option that comes up once the driveshaft is out is that it’s not a bad idea to replace all the u-joints rather than just the failed one. The labor time to replace another u-joint on a driveshaft that’s already out on the workbench is .3 of an hour. So to do the second u-joint on a driveshaft adds about $50 to $70 to the job, again depending on the parts used. On a two-piece driveshaft there is an additional center u-joint, which would be another $50 to $70 to replace as well.
On a 2000 Jeep Cherokee with a 4.0 liter engine and four wheel drive, replacing a rear u-joint would also come to about $120 to $140, and Dana is also the OE manufacturer. There is, however, a difference in the front driveshaft in that it uses a double cardan joint at the transfer case. This is a special u-joint assembly that employs two u-joints in a carrier with a stabilizing device between them, essentially for strength and smooth power transmission. If a u-joint in a double cardan assembly needs replaced, then both joints are replaced, and the procedure is a little different and more time consuming, taking a little over an hour.
So to replace u-joints in the double cardan joint in the front driveshaft, the estimate would be 1.6 hours labor, plus about $60 for a pair of universal joints. The total would then be about $220. There is also a conventional u-joint at the front side of the front driveshaft, which would add about $50 to replace if desired.
On a 2004 Ram 2500 four wheel drive truck, the front and rear driveshaft u-joints are all conventional and conform to the first estimate above. However, this truck also uses u-joints at the front wheels to transmit power to the hubs. These are usually called front drive axle u-joints. If a front drive axle u-joint needs replaced, the labor is 2.3 hours, involving removing the front brakes and front hub to pull the axle and allow the u-joint to be replaced on the bench. A factory u-joint costs about $40, or a GMB u-joint costs about $20, making the job about $270 using OE parts, or about $250 using aftermarket parts.
PRO TIP - Most factory-installed u-joints don’t come with grease fittings any longer, but replacement u-joints almost always do. As the ability to maintain the grease in the u-joint is the main factor in it’s longevity, it is worth making sure that the replacement u-joint has a grease fitting.
Signs That a Universal Joint Needs Replaced
As the main job of a u-joint is to allow the smooth transfer of power, one of the main signs that one needs replaced is if there is roughness or oscillation felt under load. Another sign is if there is a clunk when starting out, or when going from forward motion to reverse.
In practice a vehicle is put up in the air, and u-joints are inspected visually first. They will seldom wear out if their lubricating grease is in good shape, and if the grease has gone they will often rust. This tends to shed a fine orange powder, so if there is a fine orange powder spreading out from the cup of a u-joint, odds are high that it needs replaced. They can also be checked for end-play or looseness at each cup of each u-joint, manually or with a prybar.
If the u-joints have grease fittings, they should be serviced with each oil change. It’s less common nowadays, so it’s best to ask for it be done or checked on.
Roughness or shaking when accelerating. In worse cases, a clunk when going from forward to reverse.
On most vehicles it’s about an hour; a little over a half hour to remove and reinstall the driveshaft, and about a quarter of an hour to replace a u-joint.