Here's a pic of all the parts you will get with your TSB
The Body Bracket bolts are located under the carpeting on the driverside transmission hump.
Remove the two screws securing the torque shaft to the body bracket
Place the new rubber boot on the torque shaft and then assemble the bronze bushing/retainer with the flat end facing the tub
Assemble the rubber gasket into the hole on the body bracket
What it looks like when all is said and done
Jeep Transfer Case Shifter Linkage TSB
(Knocking or thumping on the floor when accelerating)

About half a year after I bought my TJ, I started to notice a funny knocking under the driver side floor when accelerating or when going over a bump. It was a kind of a low "thump, thump, thump" in rapid succession and then it'd go away. Well, since I was still under warranty, I decided to take my Jeep in to have it looked at. Well, six visits later, at two different dealerships (once to see a DC specialist) and a lot of anguish, I was told that nothing was wrong and that the noise I was hearing was completely normal... "all Jeeps are noisy." Pissed off, I started to do some research on-line and on the bulletin boards and found out that a lot of people had this exact same problem. Enough so that the NTHSA issued a TSB to have it fixed. So, with a TSB number in hand, I went back to my dealer and what did they say? "Oh yes, there is in fact a TSB for this, what do you know?" An hour later my Jeep was fixed and the knocking was gone.

What I found Out

I don't know who or why anyone would design a T-case shifter linkage as complicated as this or why it is mounted to the tub but this is where the knocking is coming from. What happens is that the bronze bushing/retainer holding the torque shaft wears out and/or the rubber gasket tears on the end. This allows the torque shaft to travel back and forth too much causing one of the links to tap on the bracket on the tub. This problem can also occur if you install a 1" body lift without installing the T-case shifter drop bracket supplied with many kits.

How to Fix It

If you are still under warranty, take the TSB (Technical Service Bulletin) number below to your dealer and have them deal with it. If you are over warranty, you can by the TSB kit from your dealer for about $19.

TSB 21-09-98 JUL 98
Transfer Case Shifter - Creaking/Thumping Noise

Part Numbers
05014148-AA Torque SH 21-105-001

Although the kit comes with new bushing for every link end, the only ones I needed was the bronze bushing/retainer and gasket. To install it, you will need to remove the body bracket from the tub. In order to do this, you will find the 4-bolts holding it in place underneath your driver side carpeting. The rest can be accessed from under your Jeep and you do not need to jack anything up or remove your T-case skid.

Write-Up Update

Write-Up & Photos by: Tony's Jeep 12/09/04

1. First peel back the carpet on the drivers side floor to get access to the four nuts holding the 'Body Bracket' in place.

2. Once those are removed, get a hammer and the same socket wrench that you used to get the nuts out of the floor. Once under the Jeep you'll have to wrestle the 'Body Bracket' loose from the tub. It will still have a strong hold on the Jeep, so take the hammer and give a few gentle whacks to break the seal. Now remove the two screws (wont need these anymore) holding the 'Bronze Bushing/Retainer' to the 'Body Bracket'with the socket wrench. When the screws are removed, just wrestle the 'Body Bracket' off of the 'Torque Shaft'.

3. This part is why I was confused/cautious. I looked at the new parts, looked at the area that the new parts would go, and didnt see a resemblance. So the whole time, I'm thinking to myself "Am I in the right place?" It turns out that my 'Boot' was gone, and that the 'Gasket' tip was completely gone. So, remove what ever remainders you have on the 'Torque Shaft'. Then, place the new 'Boot' on the 'Torque Shaft'.

4. Now, put the 'Bronze Bushing/Retainer' on the 'Torque Shaft' with the flat end facing the drivers side. Slide the 'Boot' over the lip of the 'Bronze/Bushing Retainer'.

5. Grab the 'Body Bracket' that you took off earlier and place the 'Gasket' in the hole.

6. Now, wrestle the 'Body Bracket' with the newly installed 'Gasket' back onto the 'Torque Shaft'. Align the 'Body Bracket' with the holes on the tub. Go back to the interior of the Jeep and tighten down the four screws you removed earlier. Now the 'Body Bracket' should be firmly tightened against the tub. Go back under the Jeep and with the two screws provided tighten down the 'Bronze Bushing/Retainer' to the 'Body Bracket'.

Take it for a spin and you shouldnt hear the thud anymore. Now, have a beer!

Please let me know if you have any questions.

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