Rear End grinding noise

[28Zero]

I've got a grinding/washing machine noise from the rear that's been with my '78 ever since I bought it this past spring. I've replaced the differential fluid, and that didn't seem to do much, there were no particles in the old fluid either. The noise is commesurate with the speed of the car and the gear position doesn't seem to matter at all.

I took off the wheels (but not the brake assembly) and it didn't seem to matter which side I rotated (holdin the opposite side still). Is it a bad diff, half shaft bearing, half shaft u-joints, or something in the brake assembly?

When it comes time to store the car in the garage I'm going to take it apart and hopefully get it back together again. Any ideas? What should I check first?

Cheers!

[Ed]

Usually a bad diff will make a whining, purring, humming kind of noise. To me it sounds like you might have a bad wheel bearing. If you can, have an assistant go for a ride with you. He/she can put their ear down on the shock towers and they should be able to hear if one side is louder than the other.

If it is the bearings I would suggest you read up on the procedure before you tackle this laborious task. It's not hard, but I guarantee that if you go to pull the spindle pins your going to ask yourself "what did I get myself into".

On second thought you might as well rebuild the entire assembly. (Do it once and do it right.) There are several posts on stubborn spindle pins and a couple of members have spindle pin pullers that I would HIGHLY suggest you use.

Let us know what you find and we'll be more than glad to give you advice. There are quite a few of us here that have been there, done that.

Good luck

[kinfish]

I agree with Ed ...... constant noise increasing with speed sounds like worn out wheel bearing. There is an inner and outer on each axle. Once you have stub axle pulled replace both bearings. Spindle pins is worst job on a Z; replacing stub axle bearings is a close 2nd.

[mdbrandy]

Spindle pins is worst job on a Z; replacing stub axle bearings is a close 2nd.

I'd agree with that, but the spindle pin puller referred to above makes the job almost easy. "Almost".

[28Zero]

Thanks... I'll have to look into getting the right tools for the job. It'll likely be a month before I get around to that fix though.

Cheers!

[ztattoo]

Usually a bad diff will make a whining, purring, humming kind of noise.

Good luck

What needs to be done with a bad diff. that makes these sounds? The diff. on my '78 280 has those sounds, although not loud (yet!!). The sound comes one once you start moving.

Will this eventually cause the diff to seize? come apart??? Do Ineed to change the diff. altogether or just have some parts replaced / repaired? Is this a DYI or does it need a pro. mechanic?

Thanks for any input.