PSA Weird Noise Identified as FAD

[pcrawfordpt]

Noise identified and repair competed. PSA in case you hear it. A few weeks ago I heard an odd noise, a whirring/grinding noise in my '21 JTR that sounded like it was coming from under my seat. It happened mainly when going over bumps, but not always. I first thought driveshaft, but that wasn’t it. Then I thought either transfer case or transmission, but couldn’t really figure it out. Bumped into an old friend who had worked on transmissions for decades and asked him to identify the noise. He knew exactly what it was…he asked if I had an axle disconnect in my Jeep. He said we heard this same noise on the old AMC (Jeep) vehicles equipped with axle disconnects. After some interwebs research I found the Star Case/TSB. There is a plastic bushing in the intermediate shaft of the FAD. The bushing wears out and allows the shaft to drift causing partial engagement in the FAD. The fix is to replace the inner shaft, outer shaft, bushing, and sometimes collar and bearing. The real fix is likely to upgrade to RCV (bronze bushing) and/or get their FAD delete axle. My concern is only have 20k miles on my JTR. Figure it will happen to everyone at some point. Hope this helps.

Sponsored

 

[AmosMoses]

Good to know. Thanks for posting!

 

[LouisvEarlleJT]

Since the TSB came out in 2020 I would assume something might have been updated in later year JT's (and JL's for that matter). Lots of folks on here with far more than 20k miles and this is the first post I've seen of this. Good to know in case it happens though!

 

[pcrawfordpt]

Since the TSB came out in 2020 I would assume something might have been updated in later year JT's (and JL's for that matter). Lots of folks on here with far more than 20k miles and this is the first post I've seen of this. Good to know in case it happens though!

The new replacement parts still use the Plastic Bushing...

 

[LouisvEarlleJT]

The new replacement parts still use the Plastic Bushing...

That's not indicative of anything though. Plastic bushings are used in pedal linkages and those last well over 100,000 miles (even ones going back to the 80's). Plastics can have bad batches that alter properties just like any other material, which was probably the case here though we have no way of knowing. All I was saying is that if it were a wide spread issue the forum would have blown up about it.

Sponsored