About U-joints...

On the rear-end end of my driveline I noticed the U-joint moves 'some' between the cups. 'Some' as measured by my dial-indicator is .008", on axis.

Does that indicate a problem? I haven't noticed it before. Does not seem reasonable that a new joint would be necessarily any different as such movement is not in a wear pattern. There is no such movement on the prop-shaft end.


As a btw, it's a 7290 (large u-joint) driveline w/zerk-fitted u-joints. The two cups I can easily see the insides of look fine; no dimpling on the cross, well greased. Both joints are loosy-goosy movement-wise, no binding and they rotate completely.

After I greased the joint that had the movement, I could not move it as before it was greased. I'm not saying greasing it 'fixed' something...just that the movement can no longer be felt/measured/seen.

I did take the driveline out looking for a vibration source. Around 100mph/6000rpm something is buzzing/shaking the car. LOTS of things it could be, but having just resolved a vibration issue in another rig by replacing u-joints (that I didn't 'feel' as bad), I thought I'd check 'em.

Tanks!