Knocking from rear when off the gas

Hi all,

Was driving along minding my own business when all of a sudden I notice that when I let off the gas I hear a strange knock or thumping type sound coming from the rear of the car. At first I thought it was coming from the left rear but my passenger at the time thought it was coming from the right rear. It doesn't happen during acceleration, only if I am off the gas or lightly feathering it and it happens at just about any speed. The speed of the knock sounds like it is more in relation to the rotation of the tires rather than the driveshaft which would be turning faster. The '01 Coupe has about 55K miles on it and my first thought after having checked the tires was the flex disc but that's at the tail of the tranny, no? Was hoping this might sound (no pun intended) familiar to someone.

Reply » Knocking from rear when off the gas

Just a thought. Maybe your transmission mounts are worn. I really don't know about their typical lifespan. I upgrade to UUC's Red Tranny Mount Enforcers (TMEs). They are a cross between having solid mounts and the stock mounts. They really seem to have removed the tightness when shifting problem I use to have. I think it was caused by the tranny flexing under hard accelerations or turns, which were the areas I had the hardest time shifting. Anyhow, I used to experience a similar clunk somewhere back there (sounded like the differential) upon moderate to hard acceleration and then application of the clutch pedal before doing a slow upshift. Like from a stop sign doing a hard acceleration and then realizing the speed limit is only 30 mph. Again, that was fixed by installing those red TMEs. Its hard to diagnose like this without actually driving your car. I hope that may lead you in the right direction, or at least fire up some more responses.

Reply » Knocking from rear when off the gas

I would suspect suspension noise from weight transfer:

1) rear shock mounts- probably need to be replaced if haven't been done already
2) rear sway bar link- has a tendency to slip off allowing the sway bar to bang around
3) check the differential mount- hopefully that's not the problem

Reply » Knocking from rear when off the gas

Kind of embarrased to say what it was but in my own defense, it is not something that you would have come to mind. All 10 lugs on the rear wheels were loose. The question now is, how did they get loose? They were put on by a reputable shop and I haven't pissed anyone off lately (that I know of). Just glad it was fairly minor and caught in time.

Reply » Knocking from rear when off the gas

That's incredible. I trust you made your displeasure known.

These are the reasons that DIY, or at least checking on what the service shop has done, is a matter of self preservation.

Fred

Reply » Knocking from rear when off the gas

Quote:

That's REALLY scary!! Glad you thought to check them. I've heard of lugs that have been "never seized" coming loose on the track but not on the road.

Page 1 of 2