wild vibrating motion

[blue68]

I didnt know where to post this. sometimes when i'm cruising around 30 mph down old country roads my truck will suddenly freak out and start shaking all over. You can actually see the steering wheel shaking and feel it too. It's like a foward-to-back motion, and it's extremely hard to explain. It doesnt happen very often at all. It's just weird. Does anybody know what it could be? About everything under the truck is new.

[flyboy2610]

I would start by checking the motor mounts.

[Leadfoot]

THATS NOT GOOD! really it sounds a little like your cab mounts
are bad if its vibrating to front/back. or a loose steering box.

if its side to side check your tires, brakes, king pins, pushings, and steering linkage.

[69rangerman]

Not real likely, but I had a 96 cherokee 4wd and anything over 40 if I touched the brakes it would bounce so hard and fast that I was sure something was gonna drop out. It ended up being the steering damper most 4wd's have. Super scary.
Good luck

[studdmstr]

Not real likely, but I had a 96 cherokee 4wd and anything over 40 if I touched the brakes it would bounce so hard and fast that I was sure something was gonna drop out. It ended up being the steering damper most 4wd's have. Super scary.
Good luck

My neighbor just went through that with his Cherokee 4wd. A wild vibration at aroun 40. He replaced all the steering linkage, ball joints and steering box and still had the same problem. Then went down and got a $30 steering damnper and all was good.

[blue68]

I pretty much figured out what it was. After some investigation, it was my motor mounts. Apparently, there's supposed to be a thick, round flat washer on the motor mounts. I forgot to install mine during the rebuild. I put those back on and tightened the nuts down and the whole truck actually drives stiffer feeling. It's wierd how it fixed it so fast. Thanks everyone!

[flyboy2610]

You're welcome. Glad you got it fixed.