Click Noise When Starting Off

[Lawrence Coppari]

My '86 951 has begun making a click noise in the rear when I start off. Initially I thought it was the CV joints so last week I replaced both half shafts as they are over 10 years old and had been reversed years ago. In the past replacement cured any clicks I had. The rear wheel bearings have no sloppiness and are in good shape. I replaced the driver's side bearing last fall.

The noise appears when I first start off after there is a torque reversal on the drive train. It click noise only happens once then ceases until I stop again. Prior the replacing the halfshafts, there were several clicks when starting off. The single click sounds the same as the previous clicks I had before replacing the half shafts.

The transmission is the limited slip variety with the oil cooler. Vehicle has 188K miles on it and over 100 track events. Any ideas what it could be or any tests I could do the ferret out my problem would be welcomed.

[nize]

check the transmission mounts and make sure it's all sound.

[Lawrence Coppari]

Thanks nize. Yesterday after reading your post I placed floor jack under the transmission with the car on the ground. I put a little pressure on the tranny with the jack and heard the click. I'll get the car on my basement lift and investigate further.

[Lawrence Coppari]

[Lawrence Coppari]

Car is on lift. I assume the tranny is not supposed to move relative to the support arm that goes across the car. If you look at the attached picture, the part with the red blotch moves with respect to the part with the green blotch. I think I have a problem here. Right or wrong?

Look at picture in previous post.

[Lawrence Coppari]

I removed the tranny and replaced the broken bolt in the hanger. The 8.8 bolts (one had broken) were replaced with grade 12.9 bolts. The single click remains. With the car on the lift if I get under it and rock it back in forth with the tranny in gear so there is a load on the drive train, I can hear the single click coming from inside the transmission. Car has 189K miles on it and 16 years of tracking. Wonder if it is wearing out......

[nize]

that sounds like normal wear. it might be time to rebuild the tranny. it's a great opportunity to restore the LSD clutch inside also, and maybe even change the LSD ratio!

[Lawrence Coppari]

Originally Posted by nize

that sounds like normal wear. it might be time to rebuild the tranny. it's a great opportunity to restore the LSD clutch inside also, and maybe even change the LSD ratio!

Is that a job that can be done by an owner who is reasonably handy?

[nize]

have you ever disassembled and re-assembled an analog clock? that's pretty much what all the gears and springs look like inside the tranny.

i've completely rebuilt my motor to a custom 2.7 myself, but i still took the tranny to a german tranny specialist.

[nize]

really though, your tranny is probably fine, it's just showing wear from age. i wouldn't worry about it.

[Lawrence Coppari]

Originally Posted by nize

have you ever disassembled and re-assembled an analog clock? that's pretty much what all the gears and springs look like inside the tranny.

i've completely rebuilt my motor to a custom 2.7 myself, but i still took the tranny to a german tranny specialist.

Actually I have replaced gears in a Kieninger German analogue clock movement. Thanks for advice. Hopefully it is just showing its wear.