Hi, I've got a 93 Surf and I've searched the forums here quite a bit and haven't found a thread that has helped me yet.

When I turn at low speeds in 2wd I can feel a vibration in the truck. It usually starts a little ways into the turn, then stops while I finish the turn, but I can feel it come back as I turn the wheel back to centre. It doesn't make any noise driving in a straight line. I'm not referring to the full lock/steering stops issue, I know all about that.

It seems particularly bad in reverse, like when I back out of my driveway. Parking lot maneuvers often cause passengers to ask what's wrong with my truck. It doesn't seem to make the noise in 4wd on a loose surface, or at least it's a lot less noticeable.

Any idea what my problem might be?

Thanks.

 

I had a problem with my truck for a while where one of the bolts holding a brake caliper on came loose (the front bolt on the drivers side caliper). It was especially sketchy in reverse, as the caliper actually lifted a little and started snatching at the wheel its self. Maybe check that out?

 

Any ideas? Yeah, brake calipers like spudenater said, and / or CV joints and / or bearings. If your tires are cupped very badly, I could also see this causing a vibration, but this sounds more severe than just cupped tire tread.

 

My mechanic ruled out cv joints when he looked at it. He's had the wheels off and looked at the brakes, and didn't notice anything unusual. My suspicion and his is that it could be a problem with the diff, anybody know any tests that would help me pinpoint or rule out a potential problem with the diff?

 

Do you have a diff lock?

 

I don't think I do, but the thought of it being diff lock noise did cross my mind. To test it out do I just need to get one rear wheel off the ground and see if the other will turn?

 

Basically. See if they'll both turn with one in the air. How you choose to do that is up to you...

 

I guess that gives me a good excuse to do some wheelin! My rear diff has an lsd, if it's functioning properly shouldn't I still be able to drive the wheel on the ground with the other one off the ground?

 

My problem may be solved! My mechanic said that I should try putting a bottle of AC Delco Limited Slip Diff additive into my Diff just in case the fluid I put in the diff wasn't compatible with my diff. I put the fluid in, and it still gave me a small vibration as I backed off the driveway, but by my next turn it wasn't doing it any more! I've taken it out twice now problem free! Thanks everyone for your help!