01S2Roush

I've been having this sound coming from the rear for a long time, I was sure it was my axle bearings. So I just had them replaced (and since the gear box was getting opened I went ahead and put in 4.10s along with new pinion bearing and seal) I also upgraded the axles at the same time, but low and behold the damn sound is still there! Only when I'm driving slow and turning slightly, what else could it be?! It's almost like a grinding sound. I'm still breaking in the new gears and I'm looking forward to going nuts with it but that sound scares me. Any ideas at all?

Urambo Tauro

A grinding sound could be a problem with your brakes. Are you sure that it only occurs during low-speed turns, or could it be that the grinding sound is getting covered by by road noise at higher speeds?

WJL

Just some wild A$$ guesses U-Joints, Trac-Loc Clutch Pack, Brakes, frozen caliper

I did the whole break-in thing for 100 miles, however with that said my buddy put 4:10's in Friday night and went racing on Saturday never had an issue, that was like a year ago

01S2Roush

Thanks guys, the sound is there at slow turns regardless of whether or not I'm braking or pushing in the clutch, even when slowly coasting. So I've pretty much ruled out the brakes, if it were the clutch it would only happen when I'm actually using the clutch right? Yes there is a chance I'm just not hearing it at high speeds but driving in parking lots is pretty much the only time I hear it at all. Doesn't a U-joint issue get louder at higher speeds? The guy at the shop who was a dick asked me why I didn't upgrade the carrier while doing everything else, I wasn't sure what he meant. I even thought about maybe a broken spring??

Urambo Tauro

If you only had the gears, axles, and pinion bearings/seal changed, I could understand why the shop might be disappointed. That would have been an excellent opportunity to complete the overhaul with carrier bearings and fresh clutch-packs while everything was open.

But back to the noise: Just because you're not actively braking doesn't rule out a dragging caliper. Might want to have a look at the dust shields back there too. A bad transmission clutch assembly would not create a rear-end noise.

I don't think a U-joint would cause a grinding sound, at least not without causing some bad vibrations. But I digress; U-joints are easy to diagnose. Just try to wiggle the driveshaft around; it should be solid.

01S2Roush

OK great, to test my calipers I should jack it up and try to move the rotor with the E-brake off correct?

school boy

Easy way to test non-moving, put the rear of the car on jack stands, put the car in first and let someone listen where the noise is coming from.
If it was the brakes, it would only get louder if there were metal on metal contacted while braking. If pads are good, The sound would most likely go away under moderate braking.
Like mentioned above, check your dust shields. Will constantly make noise while moving.
Check to be sure suspension is tight and not binding.
To me, it sounds like a u joint since its coming from the rear of the car.

01S2Roush

Thanks guys, I'm thinking it may be a caliper now being that at times I hear a thump thump thump when turning slowly, I'm going to replace the calipers this weekend hopefully that will be it. Thank you!!

01S2Roush

OK I replaced the rear calipers and pads, noise is still there. However I don't think I bled the brakes correctly because I have to push the pedal down farther to brake when it should be the opposite with new pads. Also do I have to bleed all four brakes even though I only replaced the rears? And if it's not bled could the new caliper still be sticking until it's bled correctly?

Urambo Tauro

I think you should re-bleed the brakes thoroughly until the pedal feels right. It's possible that a new (re-manufactured?) caliper is sticking, but not likely.

At any rate, having the rear in the air was a good opportunity to put the transmission in neutral and turn the wheels by hand to verify where exactly the grinding (or is it thumping now?) is coming from. Did you confirm that the old calipers were indeed problematic before replacing them?