Strange Squeal

I have a 2000 GMC Jimmy, 2dr, 4wd, v6, 101k miles.

There is a strange squealing (metal on metal) noise I can't seem to figure out. I have all disc brakes, and all of the pads are good, front are all new, rear aren't too old, but I checked them and have plenty of life left.

The squeal happens when I am accelerating, and only in Drive (going forward) in 2wd or 4wd, but not at all in reverse (tested it by going in reverse down my street). Squeal gets faster and more high pitched as I increase speed until it gets so high pitched I no longer hear it. Taking my foot off the accelerator makes the sound dissappear. It does not appear to be related to the brakes, since the sound goes away even if I do not press the brakes and I just release the accelerator.

In park, or with my foot on the brake, pressing the accelerator does not reproduce the squeal.

If I let the Jimmy roll in idle without pressing the accelerator, the squeal occurs but slowly.

Any ideas?

Perhaps I should note that the sound seems to come from the rear of the vehicle.

No ideas? Me either.

Anything?

There are brake shoes behind the rear rotors for the emergency brake did you check them?

Thanks for the reply. Yes I did check that. I would assume if the noise was caused by the brakes it would stop when I pressed the brake pedal, or if it was the e-brake it would be a constant noise. This metal-on-metal squeal only occurs if I have the accelerator pressed and it stops immediately when the accelerator pedal is released.

I guess this is probably one of those situations where a qualified mechanic needs to take a look, just thought I'd check and see if anyone out there ever had a similar problem.

Try taking a look at your U-Joints on your drive shaft assembly, Sounds like there either screeming for grease, or you got a bad U-Joint. Post back your fundings.

Thanks, Gabe25, I'll take a look at that tonight and post back tomorrow. Should I be checking for movement? Also, how would I grease them, are there zirk fittings?

Thanks, Gabe25, I'll take a look at that tonight and post back tomorrow. Should I be checking for movement? Also, how would I grease them, are there zirk fittings?
The only movement will be on the back lash of the rear end spider gear. The U-Joints should not have any play. Yes, there should be zirk fitting on all of your U-Joints. If they don't look for a plug and replace them with zirk fitting. Good luck.

Got under there to take a look, and found no way to grease the u-joint. Took a look at my hayne's manual and it said if the U-joints need servicing to replace them. Looks like that's what I'll be doing. The squeal is definitely from the u-joint though.

Got under there to take a look, and found no way to grease the u-joint. Took a look at my hayne's manual and it said if the U-joints need servicing to replace them. Looks like that's what I'll be doing. The squeal is definitely from the u-joint though.
OK, Make sure that you replace them with OEM parts, and ask them if they come with grease fittings. This way you can grease them and make them last longer. Good Luck. Let us know how you turn out.

Finally got to fix it over the holiday weekend.

First things first, rent a u-joint press to get that thing out of there if it's never been rebuilt. They use a plastic injected retainer to keep it in. It took a lot of trying to hammer it through and questions to a mechanic before I figured that out.

Other than that, the job is pretty simple. The only problem I have is that it's kind of hard to get to the zirk fitting to grease it.

And the noise is all gone. Thanks for the help Gabe25.

Finally got to fix it over the holiday weekend.

First things first, rent a u-joint press to get that thing out of there if it's never been rebuilt. They use a plastic injected retainer to keep it in. It took a lot of trying to hammer it through and questions to a mechanic before I figured that out.

Other than that, the job is pretty simple. The only problem I have is that it's kind of hard to get to the zirk fitting to grease it.

And the noise is all gone. Thanks for the help Gabe25.
Your Welcome. Glad everything went well. Try look around and see if you can find a narrow tip for your grease gun. I don't know if they still make them I got mine around 20 years ago. Old School. Have a great week!!!!!!!!!!