Been chasing a couple of clunking noises coming from both sides in the rear of my 2001 GP GT. Started by getting the rear up on jack stands and yanking on the different components to check for tightness. Everything seemed ok (tires were off) so put tires back on and removed from jack stands. Next I went into the trunk to try to get to the shock tower brackets and nut. The bracket bolts were tight (real pain to get at, let alone get a torque wrench in there) but I could not get the rubber covers off the tops, so I could not check the nut. While I was putting the junk back in the trunk I remembered reading somewhere that the spare sometimes gets loose so I check it. Sure enough it was loose and when I rocked it back and forth "clunk-clunk" (it sits in the bottom of a big round "drum" so the noise is amplified). Thought boy that was easy and took the car out for a spin. 80% of the bumps that previously caused the car to clunk did not have the same effect. It seemed when I crossed bumps on an angle rather than straight on there was still a clunk noise (still got some noise straight on but much less). In the pursuit of the remaining 15%, I pondered if a 13 year old car with 222,000 km was fixable at all. Well I had fixed almost everything else on the car, so wasn't going to stop now. Put the car up on ramps at the rear (this would keep the suspension active/under load) and using a crowbar I tested every bushing I could get at for side to side play (Trailing Arms, Stabilizer Bar and Spindle Rods). I also checked the Suspension Support to frame mount. Everything seemed tight. Only thing left was to check all the various bolt and nuts to see if they were to spec (torque). Started by removing one tire at a time while on jack (really need to be on jack stand as this step involved some force be applied at weird angles). I got a hold of the torque specs listed on this forum and went about checking each bolt and nut I could find. I tried turning the bolts first and if they were turn able, I torqued to spec (some were hard to get the torque wrench in there, so I used best guess by feel on those). Almost all were tight except THREE. I had replaced the trailing arms about 1.5 years ago and had used the torque wrench to tighten all the bolts and nuts, so they were the last thing I checked and sure enough three could be turned.
Drivers Side Upper, Passenger side Lower and Passenger side Upper (my clunking was worse on the passenger side so it made sense). Torqued them to spec (I think it was 81 lbs top and 100 lbs bottom-the list is available on this forum). took the car for trial run and NO CLUNK at all. The car rides like new and no abnormal noise from the rear at all (front is all new parts and it did not have any issues). Took me about a month to resolve, but worth the effort (even though I did it in my small garage with no hoist or power tools). I shudder tho think what this would have cost to have done by a dealership, who tend to replace parts instead of investigating.