ericshaw

In first and reverse I sometimes get this thump or a clunk off the line (fast or slow)... it's got me worried. My friends say its the rear suspension, but they all drive shˇtstains... uh... mustangs. :D I think it might be a gear issue but she seems to be fine 90-95% of the time. :confused:
~ eric

Kingt

You may need to add some GM positraction additive. As it looses it's effectiveness it will cause a rear end noise. This could be all that's wrong.
How long has it been since the diff. lubricant was changed?

Madmikeee

That Thread title is just WRONG!... Too many harrassment options, Can;t take the pressure!.. AARRGGHH!!!

Kingt

Don't blame him he's 98 years old. He'll be dead before he finds the problem.

:lol: :lol: :lol:

BeaterShark

I had a problem like what you describe. Turns out that I forgot to tighten up the rear-end mount. Once I tightened it up, the clunk went away.

jbroughton

Eric, as Kingt mentioned, you may just need to add some GM Posi Additive to the rear end, especially if you hear it/feel it worse when making tight turns at low speeds. Probably also a good time to check your U-joints, both on the drive shaft and the half shafts. I lost a bearing cap from one of the u-joints in my driver's side half shaft one time - if I had gotten into just one hard time, it would have made a huge mess! Luckily, I managed to limp home with it. Always a good item to check any time you're under the car.

Jeff Broughton
qwikv6@hotmail.com

Cali,68,L-79

I swear my rear end has never been lubricated, the original lube tag sits under 3" of dirt and it looks as if a wrench/ socket has never touched the lube bolt. The uniformity of dirt makes it impossible for me to see that anythings ever been done to the rear and it drives perfectly. Knock on wood!! :smash: :smash:
Just thought I'd throw that out there for all the guys that complain their Vettes always breaking down, good testiment to the General.
:cheers: :cheers:

Cali,68,L-79

Eric you know we are all being nice. That subject line is too easy not to RASS you. :lol: :lol: :lol:

MotorHead

I forget exactly what it's called but it's a rubber bumper stop thingy for your rear end and that might need to be replaced. :D

vettesite

It's called a pinion snubber bushing/cushion or the lower rear differential carrier bushing. I think that might be your problem. It's centered right between the rear tires. When this bushing gets old or falls out the differential slams into the frame and metal on metal is not a good thing.

http://store.yahoo.com/zipproducts/zip-su-390.html






[Modified by vettesite, 3:17 PM 6/17/2002]

ddecart

Yup. Time to check the rubber mount. That's a fairly common cause of a rear end thunk. Or else it could be a rear diff a little out of whack. A bit too much lash in it perhaps.

Dave

C3 Shark Tank

I have to second that, mine was very grungy and when the old ring/pinion were pulled out they looked brand new...not a mark on either of them.

I'm voting with the guys who say the problem is the front pinion mount bushing. :D

rmadlem

(Sorry, I just can't resist.) Neither has mine !!! :cheers:

Chris Fowler

I'll second that. I had the problem last year.

rob75383

Now I'm curious...
I have the reverse shift clunk.
Along with a "thump" that occurs while hitting and releasing the throttle when cruising.
I installed the rear x-member isolators disks from VB&P, plus spherical end camber rods, a new diff. front bushing (poly), a 3.70 diff., rebuilts trans, and all new u-joints. This was over a year ago, they were all installed at the same time, and I've had the "clunk", bump, thump whatever, since day one.
The clunk going from park to reverse doesn't bug me as much as the clunk that occurs when I tap the gas pedal.
I've checked everything except for the ring to pinion lash, and I really hope that that's not where the problem lies.

John2

This may sound silly. Check your battery, it may be loose. I had the same thump while autocrossing, I looked under the car for weeks. Then I looked in the car and found the problem. Good luck.

John

Calm Screamer2

Nope...Not touching that one!

ericshaw

"I swear my rear end has never been lubricated" :eek:
Yeah, I realize I left myself open with that one... that doesn't sound too good either does it...

Anyway I think it was my jack sliding around a bit but I'm going to check all the above mentioned to be on the safe side.

Cali,68,L-79

:lol: :lol: :lol: :lol: :lol: :lol: :lol:

Rooster

if it's that close to your ****, you may want to check & see if transmission isn't coming loose on you. If that's snug, e-brake cables, or exhaust tight as well? wheel bearings?