Loud thumping from underneath....

Cherikon · Nov 30, 2005

I have a 96' XJ Sport, Manual tranny, NP231 transfer case. The problem is that after a day of not so hard wheeling at Johnson Valley for the Socal XJ event, I have this loud, weird thumping sensation coming from about where my transmission/transfer case is. I unbolted the crossmember and looked around, but didn't find anything out of the ordinary. I did end up setting down on my muffler and exhaust system, but I bent them back down to where they should be. Any suggestions would be greatly appreciated. The only time I get the thumping is from initial take-off and sometimes right after I switch up to 2nd gear, even on flat surfaces. It's driving my crazy but the rest of the Jeep seems fine.

langer1 · Nov 30, 2005

Cherikon said:
I have a 96' XJ Sport, Manual tranny, NP231 transfer case. The problem is that after a day of not so hard wheeling at Johnson Valley for the Socal XJ event, I have this loud, weird thumping sensation coming from about where my transmission/transfer case is. I unbolted the crossmember and looked around, but didn't find anything out of the ordinary. I did end up setting down on my muffler and exhaust system, but I bent them back down to where they should be. Any suggestions would be greatly appreciated. The only time I get the thumping is from initial take-off and sometimes right after I switch up to 2nd gear, even on flat surfaces. It's driving my crazy but the rest of the Jeep seems fine.

Bent drive shaft. Theres no way to bend the exaust without hitting the driveshaft too.

Cherikon · Nov 30, 2005

I'll look into the driveshaft, but it seriously sounds like something is thumping right under the passenger seat.

black93xj · Nov 30, 2005

The exaust is flexing up and hitting the floor and or tranny crossmember. Thats what mine was doing and the sound was exactlly like you describe.

Cherikon · Nov 30, 2005

black93xj said:
The exaust is flexing up and hitting the floor and or tranny crossmember. Thats what mine was doing and the sound was exactlly like you describe.

Yeah- now that I have read through a few threads on that "sound" it seems to be the exhaust. I did notice the exhaust hanger that is attached to the tranny mount is warped and out of position from what it should be.

Loud thumping from underneath....

Cherikon

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langer1

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Cherikon

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black93xj

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Cherikon

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