i was driving along 80 pobaly going some were around 70 75 and all of a sudden a hear a knocking sound coming from the back or middel of my car i ignore it till i get of the freeway wen i do it gets worst and louder so i dont chance it and have a buddy come tow it home i think its my tranny but im not really sure any body have an idea wat it is

 

my guess would be tranny mount, or U jount.

 

I had a broken tranny mount before on my L98 and the only time I would get a clunk sound was under hard accelration but while crusing at any speed the tranny just sits on thr crossmember without a problem. so unless your trannys coming un mounted from the engne block Causing more wiggling then noraml I would count that out. I would check rearend and axel bearings.

 

Does it stop when the car is parked at idle? Tell us some more. You said the noise was in the rear of the vehicle. Anything else?

 

busted shocks!

 

it dosent do it when im parked but it dose do it wen im at low speed's also and its either coming from the back or the middle

 

There are a lot of things in the back or the middle of your car

 

yea i know that i just wanna know if some one else has had this problem or have an idea wat it is

 

shocks or mounts...

 

U joints knockin around?

Only way to know is to get under there and have a look

 

I've had different knocking noises before and they sure can vary in the problem. What I find interesting is that it was an all of a sudden issue. Usually they creap up on you as they gather intensity.

Do you have a safe way to get it up in the air high enough to where you can safetly crawl underneath? I'd start by trying to move the driveshaft and see if there's noise or extra play. The rear shock does break and it should be a visual obvious- plus it's one of those things that happens suddenly. Once you're under and not seeing anything, get someone to start it up and move though the gears to see if you hear the noise BUT BE DAMN CAREFUL that you can trust the other guy not to drop the car on your head.

If you still don't find anything; I'd suggest getting a 2-3 foot lenght of PVC pipe and someone to drive it while you're using the pipe as a stethescope to narrow down the clunking area. That usually works like a charm. Chevrolet did use the transmission as a support spot for tying down the chassis, so keep that in mind as yer looking for signs of the issue. Good luck and DEFINITELY post whatcha find. Nitro-Nick

(hah! We just started our Wednesday Night drag racing 2008 season program last Wed and I was lucky enough to take 1st place in my class!!! That wuz fun. To bad it wasn't in my IROC Beaver...)