Chasing Vibrations
 

Had been posting progress on another thread, but as that OP has disappeared (don't you just hate when that happens?) rather than hijack that one I'll start my own.

Previous story:

https://www.cherokeeforum.com/f2/ano...250845/index2/

Rear tires are 26 months old, with 7000 miles, but found this:

https://www.youtube.com/watch?v=O7p_...ature=youtu.be

and thought good news bad news (found problem but that tire is obsolete so now I need 4 new tires). That turned to more good news bad news when at the tire mart for an alignment (lifted 2 inches so that was totally whacked) and get some credit for a manufacturer defect, the suspect tire was put on the high speed balancer there was NO visible run-out.

I guess next up is go back and see if the axle itself has an issue, but I'm really not seeing how a axle could bend and create a movement like that.

Just replaced that rear wheel bearing which did have some excessive play.

Another thing I think I need is new spiders or shove some more shims in there. I think they're sloppy and I get accel/decel clunks after been driving for awhile (assuming something heats up). But again, don't see how bad spiders could create wheel motion like that.

Oddly, the guy who drove it around back says "You need new motor mounts". I said "Yeah I'm getting there". Although honestly they look good by eyeball and don't move a lot when crowbarred.

Wonder if they say that just to defer the issue.

I'm so cynical.

60 bucks at the recycler for a new old axle. Not a killer to fire the parts cannon.

Rotated the wheel to a different position on the axle and the runout (technically "radial runout") is gone.

Gotta mark that on there somewhere.

Is that your video of the actual problem - or just a video that shows a similar problem?

Because I don't think what that video shows can be the axle. It is showing what is most likely a wheel problem, or perhaps a tire problem.

If it was an axle problem the runout would cycle back and forth between a low point and a high point. But the video shows a tire that is stable through most of the rotation - and then has a sudden "blip". That has the hallmarks of a flat spot in the wheel. From hitting something like a pot hole.

Whatever that wheel/tire is doing won't go away by rotating it to a different position - but it can definitely change what you feel/sense in the cabin. Tire shops often put the worse wheel on the rear passenger side for this reason.

Yep!

Take a look at what it's doing now:

https://www.youtube.com/watch?v=zkbN...ature=youtu.be

Was 110% sure that was the problem too. But saw for myself on the high speed balancer it was fine (for an $85 tire anyway). And looking at it now there's simply nothing to fix. I know it's still a rear tire and they didn't pull a switchceroo because it has the residual bluing on it. They could have switched it to the passenger side but the passenger side is fine too.

OK I may be done!

Had a fairly hefty deep vibration between 20 - 30 MPH. Pulling the transmission mount revealed:

https://cimg5.ibsrv.net/gimg/www.che...46cee9b448.jpg

Half of it has separated, and this was not visible even when crowbarred.

Anyway, that vibration is gone now too.

Nice find! Good t know that kind of problem can hide even from the crowbar test!

I think I'll be looking mine over more closely....