99 tahoe rear axle

[Rick_Grff]

With the rear end on jack stands, emergency brake off, transmission in park, front tires chalked. Should my rear tires be able to rotate because they do. They rotate in the opposite direction.

 

[RST Dana]

With the rear end on jack stands, emergency brake off, transmission in park, front tires chalked. Should my rear tires be able to rotate because they do. They rotate in the opposite direction.

That’s normal. If you had a locker, limited slip, etc differential it might be difficult to spin while in park since the mechanism would cause resistance. If you place it in neutral, both would rotate in the same direction if your diff was limited slip, locker, etc.

 

[Sean James]

Thats for making really tight turns. Seriously, when both wheels are on the ground, everything works. This is totally normal. Thats why they call it a differential, one spins a different" way than the other when its off the ground

 

[Rick_Grff]

Thanks for the answers. I'm still trying to figure out what's clunking when I leave a stop sign. I removed the driveline and there is some side to side movement from the yolk on the pinion gear. I drained the differential took off the cover there is no metal chips or flakes on the magnet what so ever. There seems to be alot of backlash when spinning the pinion gear. Nothing seems wrong inside to be making a clunking sound when leaving a stop sign. I'm lost now I don't see how the brakes would stick. If I use the emergency brake to stop it doesn't clunk. Did I just answer my problem? Its got to be the brakes then right?

 

[drakon543]

i dont have any side to side movement in my driveline. the tcase has an output shaft bearing then the universals then the rear diff input bearing. you shouldn't have any movement besides rotational or the front spline moving in or out of the tcase as your rear moves up or down. if you have movement outside of that you found your clunk. also rear drums can be noisy or even completely bind up if the pads are put on backwards.

 

[SnowDrifter]

Normal. It's how diffs work. If you have a locker and want to see it work, or want to see if you have a locker, grab one tire and spin it real fast

 

[alpinecrick]

I'm still trying to figure out what's clunking when I leave a stop sign. I removed the driveline and there is some side to side movement from the yolk on the pinion gear. I drained the differential took off the cover there is no metal chips or flakes on the magnet what so ever. There seems to be alot of backlash when spinning the pinion gear. Nothing seems wrong inside to be making a clunking sound when leaving a stop sign.

Driveline clunk on GMT400's is a very common problem. The output on the T-case (NP241's, 243's and 246's) and the slip yoke on the driveshaft are splined, and the splines bind up when starting out or when the 4L60E's shift, sometimes when they 3-2 or 2-1 downshift also. The fix is a nickel plated slip yoke for the driveshaft. They used to be in the $250 range, but I see Amazon has them for $100. Don't know if it is the same quality as the $250 one.
https://www.amazon.com/APDTY-708613-Driveshaft-1992-2005-01-04-17-004/dp/B00C8E8BH0

Don't grease the slip yoke, it will temporarily stop the clunk, but the clunk will return in a couple thousand miles and allegedly will contaminate the T-case fluid. GM even has a bulletin out that says not to.

 

[Rick_Grff]

Clunking problem solved! The driver side rear brake was sticking I went with the cheap wheel cylinder replacement a few months back. It was only pushing out on one side causing the brake pad to get stuck and the return spring didn't return until I started moving the clunk would come from the slop in the pinion when the brake released.