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Thumping under floor board

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Old 07-17-2011 | 07:47 PM
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MileHiXJ's Avatar
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From: Highlands Ranch
Year: 1991
Model: Cherokee
Engine: 4.0L HO
Default Thumping under floor board

Today I started hearing a thumping noise under the passenger side floor board when I accelerated from a stop and dumped the clutch a little quick. If I keep the revs high and slowly let out the clutch pedal, no problem. But if I dump the clutch quickly, I get a long series of loud knocks from under the floor that only go away if I push the clutch back in. Any ideas?
Old 07-17-2011 | 07:50 PM
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Bad trans or motor mount? Worn suspension part?

Have you looked under at all?
Old 07-17-2011 | 08:00 PM
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From: Highlands Ranch
Year: 1991
Model: Cherokee
Engine: 4.0L HO
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Originally Posted by Gee oh Dee
Bad trans or motor mount? Worn suspension part?

Have you looked under at all?
Not yet. Just spent the evenings last week and all yesterday changing the upper and lower ball joints on both sides, a tie rod and both of its ends, and replacing an oil covered starter.

If it was up to me, I'd be under the Jeep right now, but the wife is a little tired of it monopolizing all my time, and from the mess it makes.

So while I was watching tv with her tonight, I thought I'd through the idea out there.

Motor mounts is what I am fearing. The look like a b*tch to change. And the ball joints took a lot out of me last week.
Old 07-17-2011 | 08:01 PM
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+1
Engine and/or transmission mount(s)
Either that or aggravated gnomes

Last edited by Turbo X_J; 07-17-2011 at 08:04 PM.
Old 07-17-2011 | 08:04 PM
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From: s.w. iowa
Year: 1991
Model: Cherokee
Engine: 4.0
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sounds like a ujoint in the one of the drive shafts or possible the u joint in the axle shaft it self going out
Old 07-18-2011 | 02:28 AM
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From: El Centro, CA
Year: 1988
Model: Comanche
Engine: 4.0L
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x2 mounts or u-joints
Old 07-18-2011 | 03:14 AM
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Year: 1990
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Have someone ride in back. If its u joint theyll let you know.
Old 07-18-2011 | 05:39 AM
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Year: 1998
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mine did the same noise sometimes and is week mounts allowing the exhaust to thump the crossmember or floor board.
Old 07-20-2011 | 11:18 PM
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Blue88's Avatar
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From: Seattle, WA
Year: 1988
Model: Cherokee
Engine: 4.0
Default exhaust thump

mine does it too. It's the exhaust pipe hitting the cross member. I put a piece of floor tile (bc there was one on my garage floor and it can handle the heat) between the pipe and cross member. Problem solved and it did not create a new one.
This noise drove me crazy. I thought it was the u-joints then the T-case.
Old 07-20-2011 | 11:53 PM
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Passenger motor mount is bad. I had the same problem with my 89.
Old 07-21-2011 | 12:05 AM
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Year: 1995
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Engine: 4.0 High Outout I6
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its the leprachaun in the trans telling you to be nicer to the clutch
Old 07-21-2011 | 09:37 AM
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Originally Posted by Brett
its the leprachaun in the trans telling you to be nicer to the clutch
Yours has one of those too?!?
Old 07-21-2011 | 09:40 AM
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I have an auto... he is in the tourque converter lol
Old 07-21-2011 | 09:51 AM
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From: Hutchinson Ks
Year: 1997
Model: Cherokee
Engine: 4.0
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Originally Posted by Brett
I have an auto... he is in the tourque converter lol
thats funny
Old 07-21-2011 | 10:38 AM
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From: Michigan
Year: 2000
Model: Cherokee
Engine: 4.0 HO
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i got the same noise but on the driver side... lol and only when im driving in the yard!? lol maybe the leprechaun doesn't like the grass? its tickling him... haha


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