My Z28 has 198,300 miles on it!!! However, the transmission was replaced with a brand new t-56 at 178,000 in October 2010. My rear end was rebuilt at 174,000 mi, it got new bearings, but used the original gears. the driveshaft was replaced with a used one (unknown miles) at 137,000. All that being said, My question is i feel like the is an excess amount of slack, or play in the driveline. Occainsionaly when i pull into a driveway or something like that, clutch in just rolling i hear some strange noises comin from back there. i jacked the car up, both rear wheels off the ground, put it in neutral and grabbed one wheel. started totating it forward and back and there seems like a lot of slack is there. I think thats the noise im hearing. any thoughts? What are some tests i can do to figure out whats wrong. I've only had the car since 187,000 miles, got it from my uncle who did all the previous maintanence.

Some other info: It has new Shocks on the rear, lower control arms replaced with new bushings, wheel bearings are OK.

 

there is going to be a little bit of play in the rear end when turning the wheels, the best bet is to grab the pinion itself and roll it back and forth to see how much play there is. When setting up gears, the shop should've set the backlash correctly, if they didn't, this could cause premature gear wear (due to a bad pattern) and/or breaking of axles and driveshafts in high shock situations

 

Yeah thats what I've Heard. Driving between 55-60 in 6th gear i hear a faint "hum" from the rear, My uncle said that car has done that ever since he got it, it had 41,000 miles when he bought it. Since the rear was torn apart 24,000 miles ago, put new bearings in, but kept the original gears, i assume the gears weren't worn badly. Should i have the shop check the back lash? I really feel like there is too much.

 

This z28 has been extremely well cared for. My Uncle changed the Diff. fluid every 30,000 miles, he's replaced all the wheel bearings. The engine has 198,350 miles as of today and is still great, idles with ~40 psi when hot using M1 5w-30. the ONLY thing that bugs me right now is that occaisonal "click" or a clunk from somewhere in the drivetrain.