A little background info on this: I started noticing a distinct clunking noise coming from the front end when shifting to drive or reverse, and when accelerating from a dead stop. Occasionally going over bumps or coming to a stop I would hear it, but rarely. It was hard to tell whether it was originating on the driver or passenger side, but I'm leaning towards the driver's side. I replaced the transmission mount, the transmission mount bracket, and the control arm on the driver's side. This did not seem to have much affect. A few weeks later, I decided to replace the lower motor mount. Doing this completely eliminated any clunking noises. I figured the mount was just worn allowing the motor to rock excessively.
Fast forward 5-6 months and now the clunking has slowly returned, but ONLY when shifting to reverse this time. It also does not occur every time when I accelerate like it did before, and when it does the sound is less pronounced. I thought maybe the nuts on the motor mount were coming loose, so I double checked and they appeared tight. Next I checked the nuts and bolts on the transmission mount, mounting bracket, and the subframe bushings. I tightened up the two bottom nuts on the trans mount, two bolts on the bracket, and the two front subframe bolts. Tightening these seemed to have a distinct affect on quieting, but not completely getting rid of, the clunking noise. Its probably also worth mentioning that I checked the sway bar and its bushings, right side control arm, end links, and bushings in the torque struts. None of these appeared damaged or worn. The car is an 04 gtp with 146,000 miles on it.
Now, my question is what are the torque requirements for the subframe bushing bolts? When I checked them, the rear two appeared very tight, but the front ones were noticeably more loose. I tightened them, but figure maybe not enough. I have the factory service manual, but can't seem to find it in there. Is the spec the same for both sets? I can't seem to find a reliable answer for this online. This may be my guess as to the source of the clunk. The motor mount may have been a contributing factor, but obviously not the sole reason. I guess the subframe bushings themselves could be worn, but some people have said this probably wouldn't happen at only 146k? Anyone have any other ideas?
