I have a, new to me, '94 6cyl Cherokee. I've had the transmission rebuilt. They told me there is a "harmonic vibration" unrelated to rpm at about 50mph. The guy at the transmission shop said it sounded like it was in the rear. It seems/feels to me its toward the front. I can feel it on my feet.

The tires all around are in need of replacement, that will come.

I got under and checked the drive shafts while in park. I'm able to move them i.e. there is some play in them.

Any thoughts on what might be causing the "vibration"? What would be the best way to trouble-shoot the problem?

Thanks

 

Tires, brakes, U-joints, bearings or worn gears. Start by having tires balanced. Trouble shoot be inspecting possible causes, including the repaired Transmission.

 

Check your front hub bearings. I have blown up two of them and both times caused a vibration at 50-60mph. Get the vibration going on an open road and turn gradually to both directions, see if it gets worse in either direction. If it does, it should be on that side.

 

You jogged my memory .... I notice the vibration lessens or goes away on sweeping left turns. We're leaning to the right, would that be the left hub bearing?

 

I would do new u-joints anyway lol

 

Btw, in general if you feel the vibes in your feet or your seat, take a look to the rear. If you feel it in the steering wheel, look to the front.

 

Where would you recommend to get parts?

 

Napa.

 

I had harmonic vibes at 50mph once, I could see in my rear view it would vibrate, I needed a whole new front drive shaft, the balance wore out or whatever, I just grabbed one at junkyard