Thumping while accelerating...

[GSXR_Chris]

I have heard this happening to people under WOT but that is not when it happens to me at all, infact at WOT it is just fine. When I am starting out in first gear at a light or a dead stop you can feel vibration under the middle of the car up to about 4k rpms and then it just goes away. This is only at low rpms. It also does this in other gears as well at low RPMs. You guys still think it is a the U Joint or not? I have heard of people filling the U Joints with Sillicone but wouldn't it just be better for me to buy a completley new U joint? Any idea how much they go for?

Chris

 

[ITSME4G63]

I have heard this happening to people under WOT but that is not when it happens to me at all, infact at WOT it is just fine. When I am starting out in first gear at a light or a dead stop you can feel vibration under the middle of the car up to about 4k rpms and then it just goes away. This is only at low rpms. It also does this in other gears as well at low RPMs. You guys still think it is a the U Joint or not? I have heard of people filling the U Joints with Sillicone but wouldn't it just be better for me to buy a completley new U joint? Any idea how much they go for?

Chris

could be your carrier bearing

Rear end thumping noise under hard acceleration fix.
The $5.00 Carrier bearing fix!

Legalese: This information is to be used at your own risk.
These facts have worked on my car, but may not fit your situation.

This fix might apply to your 1G AWD (not sure about 2G's) if you have a distinctive thumping noise coming from the rear of your car under hard acceleration or WOT.

Sorry I didn't take any pictures of this, but it is a rather simple fix once you get under the car and take a look.

The problem is your rear carrier bearing, not the bearing itself but the rubber boot attached to it that goes around the rear drive shaft. The problem is that the rubber boot is worn out and allows the drive shaft to have too much play to move around. Because of this it will sometimes allow the drive shaft to hit the underside of the car.

If you take a look under your car you will see the drive shaft going from the transfer case to the rear differential. There are two carrier bearing that go around the drive shaft and bolt to the floor pan with two nuts. The one that you need to apply this fix too is the rear one. (Although you could probably do them both if you really wanted too.)

Grab a hold of the drive shaft near the rear carrier bearing and move it around. It should not move too freely like mine did.

Here is what you need besides the tools and a jack or ramps.
1) A caulk gun
2) One tube of 100% silicone. (The faster drying the better, and waterproof.)

Steps to fix it.
1) Jack the rear end up and put it on jack stand or put it on ramps. You are going to need to be able to access the carrier bearing from the rear side of the car so you want to have plenty of room to move around.

2) Use a hydraulic jack (or something) to support the drive shaft in front of the rear carrier bearing so when you un-bolt it, it doesn't fall on you.

3) Look at the carrier bearing, you will notice on the bottom of the rubber boot there are two holes in it.

4) Un-bolt the two nuts that secure the carrier bearing to the floor pan. You will need to have the drive shaft supported by something, lower the drive shaft enough so you can turn the carrier bearing upside down while it is still on the drive shaft. You do not want any weight on the bearing or rubber boot. (Support the drive shaft with a jack stand or hydraulic jack.)

5) When you turn the bearing upside down you will see a smaller hole in the rubber boot. Now using the caulk gun pump the silicon into the hole until it starts to come out the other two larger holes.
(I used about 1/2 to 3/4 of the tube).

6) Clean it up a bit and let it sit with the drive shaft supported with NO weight on the carrier bearing for at least 4 hours or more before you bolt it back up. If you tried to bolt it back up right away the weight of the drive shaft would squeeze all the silicon out!

7) Let it sit another 24 hours for the silicon to completely cure as specified on the silicon tube. During this dry time support the drive shaft so it is in the middle of the rubber boot so that it dries centered.

When complete you have basically rebuilt the rubber boot around the driveshaft so it has no free play to slap the underside of the floor pan as it did before.

No more thumping, not even when drag racing!

Special thanks to the NW-DSM members who gave me this fix.

 

[DROOPY209]

well thats about it.........

I just did the carrier bearing fix a couple months ago.......the difference was expectacular....

the only real problem that i had, was since i have full 3" turbo-back exhaust on my red 92 talon tsi awd, i had to kinda wiggle my hand thru the 3" piping to be able to get the 2 nuts on the left off.

if you still have ur stock exhaust, you shouldnt have a problem.

make sure you do this in the morning, so it can dry the atleast 24 hours.

If you want, you might wanna repack the front carrier bearing too, the one on mine took almost a whole tube of silicone.

make sure you put a piece of cardboard or something under your car so the silicone wont stain your concrete/whatever.

enjoy having awd

 

[ITSME4G63]

yes, while youre doing this, do both carrier bearings, youll need like 2 bottles of the stuff. I didnt have much trouble with my 3" pipjng.