BrendonBJ

Hey I picked up a 2004 Lexus GX470 about a week ago and am hearing and feeling a pretty big clunking noise. With the front drive shaft out, absolutely no noise or clunk. I put a new driveshaft in and the clunking still goes crazy. Shifts from park into drive and reverse just fine but when accelerating is when I get the noise. So far all I've done is replace the driveshaft. Anyone have a similar experience with a first gen GX? I will attach a video to hear the noise.

NTH

Have you tried greasing the zerk fittings?

BrendonBJ

I did some further diagnosis and tried driving in 4lo to see what it does. This time it clunks more rapidly even without pushing the gas like shown in my first post. I then put it back in 4hi and turned on the center locker, exact same result where it clunked like crazy with no gas. Then the center locker would not disengage and I pushed the car while in neutral and now even in neutral it clunked and was difficult to push. Any ideas on what could be causing it with that update?

chiph9

There was a TSB about a driveshaft clunk, but it was for the rear driveshaft (transfer case to the rear differential "pumpkin") not the front.
Lexus issued a new part.

I had this and the new part solved it for me.
37110-60A40, cost is about $450 at the dealer. Comes with new spiders and bearings so all you do is bolt it in then grease the zerks.

Chip H.

BrendonBJ

I have driven with the front driveshaft out and the rear driveshaft in and it's smooth as butter so I would guess the rear driveshaft is good

IanB2

Should go without saying, but with a driveshaft removed you should have the CDL locked, or that center diff is going to wear itself out trying to compensate.

Have you tried with the rear shaft removed and the front in place? Also make sure you've greased that rear driveshaft, it was the subject of a TSB as mentioned due to clunking.

In conditions where it was "knocking like crazy with no gas applied", are you able to replicate the symptoms with the vehicle stationary, or does it need to be rolling to make the noise?

BrendonBJ

When driving without the front driveshaft the CDL was locked yes. I have not done anything with the rear driveshaft as there was absolutely 0 clunking and driving perfectly in RWD with just the rear driveshaft in and CDL locked. The vehicle does have to be rolling to make the noise.
I may try with the rear driveshaft out since people recommend it, but since the symptoms don't show up without the rear driveshaft I don't think it's that.
Thank you for the response!

IanB2

I just got a chance to watch your video...that's a very strange rotational noise frequency. Judging by your speed, it's making a noise every few rotations of whatever is the source, but not each rotation, if that makes sense?

Front diff oil clean, no chunks of gear floating around or something like that?