Hey,
More issues with a poor old abused vette. The rear end has some major issues. I drove it for 25 miles about two weeks ago and the back left tire got hot as all hell and the rear end started locking up while i was driving. At low speeds there was a loud banging sound like someone was smacking my rear end with a hammer.

Had to get the car towed home because it was too hot to drive and unstable. My uncle who has worked on corvettes before noticed that the car would shudder when taking off, from the back left tire. Also noted that in reverse it didn't roll freely, it acted like it was getting hung up somewhere.

I rebuilt the trailing arms and replaced strut rod bushings because the arms and **** were loose. Seems to have minimized some of the issues. Also had the rear wheel bearings done. I'm about to replace the differential fluid and put in some more positraction fluid.

It's still getting some resistance at certain points when rolling freely in reverse I notice, and it still shudders when taking off in the rear end. Not sure if posi is messed up, but it seems fine doing figure 8's. I read somewhere that the differential has bushings that can go bad, causing issues like this.


TLDR: Rear end has shuddering issues taking off, wheels arent rolling freely in reverse. Not sure if posi is messed up, but it seems fine doing figure 8's.

Also, What's the best way to check if my frame is straight without pulling the body from the car. It looks warped or like its sagging near the front right wheel to me, but I'm not certain.

 

after you change the differential oil it takes awile for the posi additive to work it's way into the differential clutches . T

 

Sounds to me like it's your clutch pack in the differential. I had my differential rebuilt and decided to put an "upgraded" clutch pack in. After the break-in period (about 2000 miles) it sounded like someone was hitting the differential with a hammer whenever I turned right or left. Gradual turns were worse than severe ones.

The garage was great in working with me to try different gear oil weights and additives, but nothing completely removed the banging except replacing the clutch pack with a stock one. No matter what gear oil / additive combinatoin we used, it always seemed to do well in figure eights, but after about 20 minutes of driving the clutches would start banging.

It can take some time for the additive to work into the clutch pack, but if the problem isn't getting better, then your clutch pack may be bad.

 

Have you checked the rear brakes or the parking brake ? Tires getting hot would indicate brake..

 

Yep. Ebrake shoes are dragging; probably a broken spring.

 

Rebuilt parking brake. Everything is new in the drum. I mated it and broke it in already. Most of the banging went away after the bushings and trailing arms were rebuilt.

Now its just hanging up while rolling with the clutch in. What's a good resource for rebuilding the positraction/Clutchpacks? I don't know the first thing about them.

 

You claimed the tires where getting hot. That is indication of something close to the wheel Not the center section. If you have rebuilt the brakes then it's possible your wheel bearings are shot...I have never seen a rear throw out so much heat it'll cook the tires. If so it's more than a clutch pack, it's shot bearings, but hot tires from the differential, that mean the half shafts, u-joints would be so hot you couldn't touch them and they too will now be junk. If your tires are hot recheck brakes and wheel bearings.

 

Had a brain fart the other day, My bad. I have no idea how I wrote tire. Meant to say back left spindle.

I took it to a shop to replace the bearings because I don't have the right equipment for that. That SHOULD be taken care of. Though, the more I think about it, the more it sounds like I got ANOTHER set of bad bearings.
I'll probably be replacing the ujoints sometime soon.

The brake callipers feel cool to the touch compared to the rotor.

Question,
When your car rolls backwards, Does the differential turn too, even if the clutch is in?

 

Yes. The rear wheels turn the half shafts, which turns the diff, which turns the driveshaft.


Dodosmike

 

The wheel getting hot does indicate a brake or bearing issue at that wheel. But, I wouldn't be surprised if you have more than one issue. I would jack it up and remove the half-shafts and rotate each wheel and then the differential and try to determine what is good and what is bad. Just replacing the differential fluid sure as hell isn't going to fix it.

 

You mentioned that you had the rear wheel bearings replaced. Just wondering if it was done correctly. Those tolerances are very precise and there are several issues that can/could go wrong if not done right. How competent/confident is the shop that did the work? Sure does sound like a brake or bearing problem to me also.

 

Is this what they told you? The bearings weren't bad, they were not set up properly. Sounds like this shop doesn't know what they're doing.

 

Haven't talked to them yet, Going over there today to figure this out. Fairly confident they did it right though, but we'll see.

 

The chances of getting new bearings that are "bad" are close to zero.

 

We'll see what happens. I have the time to play around with it next weekend. What would be a good resource for a "Correct" install?

 

Found the cause of the rear wheel lock up.

Dropped the differential on sunday and found that the PO had installed the yoke clip thing wrong, and it ended up poping off and getting chewed up by the diff.

No damage done. Other than needing new yokes because they're a bit ground up. Any suggested manufacturers and tips on install?

Bearings are still good in the wheels when I turned them. The heat is definately caused by ebrake. I'll loosen it up slightly and see if it still works.