Are you looking at an inner CV joint or an outer one? The half shafts are too small in diameter and rotate too slowly to cause a vibration, and a little play is perfectly normal. However, there is a problem like you described that is caused by a worn inner CV joint housing. I have always run into this up to about thirty five mph, when under load, as in when accelerating out of a parking lot. At the speeds you observed, there is usually less of a load on the CV joints, so the wobble is not noticeable.
The cause is worn spots on the six polished surfaces the three rollers run on. Those allow the shaft to change length as the suspension goes up and down, and as the shaft rotates. When the rollers need to run beyond the worn spots, the load on them causes them to bind. Rather than rolling smoothly, they push on the shaft which pushes on the outer CV joint/wheel bearing/spindle, which is attached to the lower control arm on rubber bushings. The steering linkage is connected to the spindle, so when the spindle is pushed back and forth, it tugs on the steering linkage and steering wheel.
In nine out of ten times, I have found the cause to be the right inner CV joint. I have only come across this a couple of times on the left one. There is no way to identify this other than to disassemble the joint and inspect it. You might be able to verify this by shifting the position of the engine. It is held in position by one of the engine mounts, and that is usually slightly adjustable. Moving the engine will shorten one half shaft and lengthen the other one. The rollers in both inner CV joints will be running back and forth in a new area. You should see the vibration change. It will get worse, better, or be more pronounced at a different speed.
Once the joint is disassembled, clean out the grease then run your fingertip over the six machined surfaces. In the unlikely event you feel any slight wave in that surface, you really have a bad one. Normally you will not feel anything wrong. Now shine a light in there and look at the reflection on those surfaces. This is where you will see the cause of the wobble. This is similar to looking at the reflection of the ground in the bodywork of a classic car.
It is important to note that you can run into this problem with a rebuilt half shaft from the auto parts store. The people inspecting the parts for reuse can easily overlook the very minute wear.
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Sunday, October 29th, 2017 AT 5:28 PM
