I took my 2008 GX470 (purchased in late March, 2008) to the dealer yesterday to change the plastic piece that covers the speedometer/tach/etc (because of scratches on the back/inside side, for the second time), and the clunk issue came up (I brought it up). They had no problem making the changes (TSB). The service manager, without hesitation, said, and I quote “I would be glad to complete the TSB” (which only technically goes through 2007), and said he would check to see if he had the parts. He did. They began to complete the TSB right then (same day), but, corporate said no, claiming my 2008 should already have the new parts. My dealer argued with them, stating that their customer had experienced the clunk (I experienced it only two times (1400 miles), and this is what I told him). They (corporate) agreed to allow the dealer to change the driveshaft, but not the arms (upper/lower, two sets of two). My dealer changed the driveshaft. My dealer said that the driveshafts were, without question, different, but they could see no visible difference in the arms (note that they did not really look closely (measure them), so there may really be some difference; I have read that the new ones are larger in diameter but do not know if mine has the new or the old). The dealer (service manager) also said that the numbers on the driveshaft don't mean much. They use the part numbers specified in the TSB, and the numbers on the driveshaft may not be the same when ordering the driveshaft by the part number in the TSB.
The service manager and I spent at least 1/2 hour looking for some mention of the VIN regarding the clunk issue. We could not find any. There seems to be nothing in the VIN that would tell them/you if or if not the clunk TSB is included. The bottom line is that the dealer has no easy way to determine if you have or not the new driveshaft and arms. They just go by complaints. If you complain, and based only on the complaint, they (the dealer) should/may apply the TSB, but corporate may prevent them from doing the entire TSB, or any of it depending on the vehicle and how strongly the dealer is willing to argue with them on your behalf. When I say prevent, I mean of course, they will not pay for it.
I have not driven the vehicle long enough to see if the clunk is gone. I have not experienced it yet, but hardly did before. Since I have only driven 40 miles since the driveshaft change (due to my three recent surgeries) I really don’t know if it is fixed. I cannot really tell any difference except that it may shift a little smoother. One last note, the service manager said that the biggest part of the clunk problem is lack of grease in the drive shaft (the end that goes into the transmission, I think, and which has no grease fitting). He grease mine up when he installed it. The other end has a grease fitting but since it is not mentioned in the dealer prep documentation only experienced techs will know to grease this as part of the prep before sale. He said, as the driveshaft gets drier and drier (grease melts or thins out) the worse the clunk will be. He gets his 2007 GX470 greased (the driveshaft) at every oil change, and we agreed that he would do the same to mine at every oil change.
Omegaman
Thanks for the information - - I'm going to follow up with my dealership sooner or later on this and although I don't feel the "clunk" when stopping, it's a different story when I have my A/C on. When the A/C cycles on, my rpms go up a bit for a brief second or two and sometimes, I feel a little push from behind. I think it may be the increase in rpm. Does this happen to you? Not many '08 owners here yet, so figured you may have experienced this as well?