Clunking noise and occational vibrations

ZONER17

MEMBER
CHEVROLET

Hey guys,

I'm writing to ask your opinions regarding my 97 chevrolet camaro w/ 5.7L and approx 109k miles.
Recently, I have noticed a rough clunking noice coming from what sounds like the tranny or a tad bit back from the tranny along with an occational vibration heard and felt inside the car around the center cousel. The thing is that the clunking noise is only heard when the car moves very slowly (ie < 5mph) and heard more often when in reverse or on an incline. Above 5mph the sounds stop and doesn't return. The vibrations heard and felt come and go every now and then (only when the car is stopped & in gear!). The vibrations stop once the car begins to move again or is placed in "Park".
The clanking noise I thought would be due to a bad U joint right? But if the U joint was bad wouldn't it clunk whenever the car is placed into gear also or when driving at normal speeds (ie >5mph?) (Which mine doesn't). P.S. The transmission fluid is not leaking and is clean and unburnt.
Please, whatever insight you can provide me with I will greatly appreciate it. Thanks.

1 Reply

KENVCR

MEMBER
105 POSTS

You are correct to think it may be the u-joint. Did you know there are 2 of them on the drive shaft?
You need to get under the car, grab the drive shaft and try to rotate it by hand (tranny in park) back and forth at the rear joint and then at the front joint.
Get any sloppy movement?
Then put the tranny in Neutral. Rotate the shaft again. This time make full rotations while applying some downward pressure. Does it feel a slight dip or wobble at any point no matter how slight? If yes, replace u-joint. If they have not been replaced before have both replaced.
Another test is to jack up car put rear axel on some really good stands. Start car, have someone inside put car into drive and just let the wheels spin. With lots of light under the car observe the drive shaft. Have the guy in the car apply the brakes before changing gears or you will grind out your tranny. Observe the shaft in both forward and reverse and listen and look at each u-joint when changing direction.
Goodluck, let us know what happens.
Kenvcr