rear clunk

[fmarin]

1973 Porsche 911T

This one has stumped me and quite a few others.

When making certain turns, I hear a single, dull clunk. It sounds like the rap of a mallet on the underside of the car towards the right rear. It only occurs on a medium-speed hard left turn AFTER a hard right turn. I hear it during city driving, but not on the highway. If I make two left turns in a row, it doesn’t occur on the second turn. I don’t hear it on right turns. I also don’t hear it when going over bumps (like a speed bump in a parking lot). The clunk occurs if the transmission is in neutral or if the clutch is depressed. The car has 90,000 miles. Since everything is original, I’ve gone ahead and replaced the rear spring plate bushings (with Netrix type), the rear trailing arm bushings (with plastic type), and the transmission mounts. I have not replaced the engine mounts as they appear solid, although somewhat “squashed”. I drove the car with the rear sway bar components removed and the clunk remained.

My impression is that something shifts in one direction during a hard right turn and then shifts back in the opposite direction during the left turn. It’s on the left turn that clunk is heard.

Could I be misinterpreting the location? Could the engine mounts actually be bad? What about the possibility of a rear bearing or CV that’s starting to go? (However, when I rotate the axles by hand there are no unusual sounds and the rear wheels don't seem to have any play when pushed on).

[ttweed]

Have you read this thread?

TT