A few weeks ago, I busted my 10 bolt with a WOT 1-2 shift. I had the ring and pinion replaced and the bearings on the carrier looked fine so the installer didn't change them. When I got the car back, I heard a grinding noise so I took it back to him only to find out that one of the ends on the differential had completely broken off. So I picked up a used auburn differential and had him press new bearings on it and reinstall my 4.10s. But the grinding was still there. So I figure it may be a brake problem and start tearing into them to see if they are rubbing, but after removing the calipers and starting the car on jackstands, the noise is still there. So bare axles are making the noise, must be something in the rear. I just replaced both axle bearings and seals just to find out that the noise is still there. So I continue trying to track down the noise and when spinning the axles by hand in the neutral, the tranny is making a strange whining noise near the tailshaft. Also when I start the car and put it in neutral, the axles are spinning. Is this normal or do I have a problem? Would it be alright to pull the driveshaft from the tranny and start the car to see if the grinding noise is from the tranny?

Its fairly hard to diagnose the noise with the car running because I have true duals. So any help will be great.

 

well you will get some wheel spin in N can you stop the wheels from moving by hand?....usually when a rear goes either your forward sprag or the sunshell goes with it...or you could have damaged the rear planet which operates 1st and 2nd

 

I haven't been brave enough to stick my hand by it to stop it.

 

The tires spinning are probably not a symptom here, may be but not likely as the Low Reverse clutches are applied in P R and L... some tire spin is acceptable in Neutral. The noise you hear spinning the unit by hand could easily be the Low roller clutch (sprag). It is normal.

How does the unit shift out? It will usually lose at least one forward gear when the forward sprag fails.

As previously stated... the sprag in the Input drum (forward sprag) is the most likely culprit of the grinding noise, and the other hard parts mentioned are certainly suspect as well. Unfortunately that is a best guess.This is not uncommon at all in a 4L60E when a rear axle grenades. Sorry for the bad news.

Any quality shop could diagnose that problem for you in a vey short period of time though... Good Luck.

g

 

Alright so I guess it could be a tranny issue. It seems to drive perfectly though until I decided to tear it apart.

Only thing is the sound REALLY sounds like its coming from the axle housing. Is it possible that the noise is going through the DS and into the axle housing? I've already asked, but would it be harmful to start the car with now driveshaft attached to the tranny to see if the noise was there without the rear spinning as well.

 

Hey , you can run the trans on stands without the driveshaft in it but it would be better if you had a drifeshaft yoke to slip into the back of the trans because the yoke helps to support the shaft with the extension housing bushing !! also if you do run it that way keep in mind you can't stop any thing with the brakes so start it in neutral an the drop it id gear . Then you can go from low to drive and back with no problem , but shut the engine off before you go to reverse or park !!!! J