Thats funny that you mention doing this because the very first time I complained of the thump that is what my technician did. He stated that he felt the thump there also and then he said OK, I know how to fix this.

Well three visits later and I am still having the same problem. Although not as consistant yet .

 

I now have 11K miles on mine and the thump has gone away. If you grease your driveline every 4-5K miles and give it time this problem will "wear in" and go away (it's called driveline wind-up, common with AWD systems, all the parts have to wear in and it needs to be lubed regularly ). Same experience with my 95 Landcruiser. I would not have some tech at the local dealer disassembling and working on my driveline, you will end up with more problems then you "thought" you started with, as some of you are now finding out. Good luck

 

The GX, LX, 4runner and LC, do not have AWD systems. They are Full time 4wd systems. The RX has AWD. The two systems are considerably different.. I have been driving AWD and 4wd systems for years. This is the first time I have ever had a "thump" situation. As for the idea or it "wearing in", I tried that with the first driveshaft. It got worse. Now with the second driveshaft, it has returned in 500 miles.

I spoke to Lexus CC today. They are aware of the issue (of course) and will be "getting back to me".

 

Now I'm starting to see what your problem is, since you know so much about these "AWD" "Full time 4 wheel drive" systems you should be able to figure out what needs to be done to fix your GX. Guess I'm not as smart as you but I fixed my thump. I also had the thump in a 1995 Toyota Landcruiser and did the same thing and it went away. Had 135K miles on the LC when I traded it and never had a problem. I think you already screwed up having the local Lexus shop replace your driveshaft, I think you realize that.

 

#1 - I had been a Mitsubishi Technician for years. I think I know a little bit about 4wd systems.
#2 - As per the TSB from Lexus, they MUST now replace the driveshaft whenever a customer complains about the thump.
#3 - Yes, I have heard of driveline wind up, working on Monteros with 4wd systems, not on AWD.
#4 - The issue appears to be gas build up in the driveshaft, and the lack of gas release causing the driveshaft to knock back after a stop.
#5 - I cannot dictate a course of action for Lexus to follow. They are bound by the manufacturer to follow the procedures they are given. I know this red tape BS all too well.
#6 - This issue was not bothersome to me until most recently. It has not improved, but has deteriorated, and will not improve with age.
#7 - With the experience Toyota has with 4wd systems, this issue should not be present on a $53000 GX or a $66000 LX. It should not even be on a $24000 Mitsubishi.
#8 - If you thik the average owner as a "solution" wants to (has to ) take his vehicle in to be "greased" every 4000miles, I think that is pretty poor.

Lastly, dont take the argumentative approach to your posts. I sat back for the last 8 months watching the thump posts and following the cases. I did not post a thing until this week after visiting the dealer. I simply posted to relay my findings. I guess since you "see what MY problem is" then you see what EVERYONE elses problems are with this thump issue.

 

Randy, good luck getting your thump fixed on your full time 4 wheel drive GX470.

 

this hasn't answered my question if the thump can be claimed for the Lemon Law!

 

Hey folks..didnt mean to start a war here..but this is for my own personal knowledge. I have a working idea on whats going on..thats why i wanted that experiment.

btw, yes I am an engineer...so entertain me.

 

Why not get out your phone book or do Google search and call a local Lemon Law Attorney. They will give you a free consultation

Good Luck

 

oh man! two weeks later, my Gx is back in da shop! now i didn't complain about the clunk yet, but now my brakes "are falling apart!" meaning that my brake axle was leaking on one side on my 20k service, now both rear axles are leaking! what's going on?!?!??!?!??!

 

ok this is it. I'm really getting pissed with my dealer. any ca dealer suggestions? preferably northern ca, I know Magnussens is a good one. other suggestions??

 

I don't understand the chatter about a thump. This truck is the best riding, driving, off road vehicle I've driven. When on the road, my friends who drive other trucks are envious. When we go off road, everyone wants to ride with us. If others are noticing what I call "sit down" when I come to a somewhat faster than usual stop, or when the a/c compressor kicks in, It's much more noticable if I am forced to use less than the best in gas. (Once had to use Arco premium....boy, what a difference in performance...yuck! My gas of choice is Chevron premium) This does not make it a bad car, it is just how it works.
My only wish is that it had more cargo room. But if that was the reason for buying a 4wd, I would drive something else.
In my opinion, this is one of the best 4wd vehicles made and I think we should remember....it's not a car, it's a 4wd truck with the comforts of a car!
(the kids and adults love the DVD!)

 

yeah except our thump, vibration, creaking seat, cladding rattle, and two rear brake leaks ruin all the fun!

 

Picked up my GX at the Lexus Service Department today. They prepared the new Drive Shaft before installing it. They followed some procedure including drilling a hole somewhere.

I could force a thump by moving the switch that raises and lowers the rear of truck. I tried the same procedure on my way home from the Service Department, but NO thump.

I never was too concerned about the thump, but since reading so much about it, I decided to have the Drive Shaft changed.

~ Cap

 

The reason that I bought the GX is mainly for its smooth and quietness. It¡¦s a humiliation when your friends are riding with you and enjoying the smoothness and quietness of the new GX and suddenly there¡¦s a big thump and everybody thought you got rear ended.

Got a new driveshaft about 3 months ago, didn't really solve the thump problem.

Now I have about 19k miles on the GX, I don't feel the thump anymore. Hope it's gone permanently.

Maybe the wear-off theory is true.