For my '91 4wd IFS 7.5".

Even at low speed, very low speed, has a kind of clunking that occurs in sync with the revolution of the tire. Almost like what you would expect to happen if a section of your tire was flattened off. It ONLY occurs when that wheel's (driver's side) hub is locked in 4wd, and even when the transfer case is in Hi2.

I do have a Lockrite in the front. Yesterday I jacked that wheel off the ground, locked the hub, and spun the tire, no obvious noise heard or anything felt. The shaft between the t-case and the diff did rotate, even though it was in 2wd. Should that happen? I wouldn't think so?

I do have it isolated to just the driver's side, does not happen if I lock in the passenger side only. I would think if it was a diff problem, I'd notice it regardless of which side was locked it, for the most part. I'm tempted to think it might be something in an axle shaft joint, but can't explain why I don't notice it when on jack stands.

I pulled the front off the hub yesterday, saw nothing obviously wrong, but maybe something on the inner part of the hub? Just didn't have time to pull it all apart yesterday.

Any hints are appreciated. Thanks!

 

Grab a hold of the CV, right where it connects to the diff and try to move it. Might be bad carrier bearings or shaft. Could also be the CV itself.

Could also be the spindle bushing.

 

Assuming the other wheel was on the ground, with the Lockrite in the front you shouldn't have been able to turn the wheel at all, or if you could, you should have heard the Lockrite ratchet clicking. Sounds like your Lockrite may not be healthy.

 

The passenger hub was disengaged when I did this, so I think the driver's side should have been able to turn. I will lock the pass side in next time and try again, just to make sure.