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Old 02-04-2015, 06:05 PM
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85 cj7 rear end noise

Hello, I have an 85 cj7 with 4.2 and 4spd t176 trans . When I driving and if I let push the clutch in to coast/slow down I get a nice humming noise from my rear end pretty sure it's a bearing but my question would be which is most likely the culprit? It happens in gear clutch in or when I'm in neutral. Thanks for the replies.

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Old 02-06-2015, 05:30 PM   #2
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Not sure what to tell ya, i will assume it a model 20. I would guess and this is a big guess its doing it in neutral the pinon bearing... but not sure..

also are you sure its not just the a clutch issue?

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Old 02-12-2015, 05:52 PM
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Yea it does it if I just let off the gas and don't touch the clutch, if I push in the clutch , and if I shift into neutral and let the clutch out the only difference is when I put I take it out of gear I don't hear it transfer through the driveline and can only hear it in the rear end...
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Old 02-12-2015, 07:45 PM   #4
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Have you checked your U joints? One may be going but not have enough play to start clunking when you go on or off throttle.
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Old 02-13-2015, 02:49 AM
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I hadn't thought too once I just got a brand new drive shaft with new spicer u joints.
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Old 02-14-2015, 08:41 AM   #6
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Probably pinion bearings so you might as well do the carrier bearings and axle bearings while you are in there.
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Old 03-24-2015, 12:23 PM   #7
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I went through this same problem , did you change your lift ?if you did i would bet it's a drive line vibration due to an increased angle, when there is no load on the drive line it ls able to rattle a bit, add a load and it stops . a bad rear end would always make a grinding or squeal sound .
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Old 03-26-2015, 02:49 PM   #8
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Rear axle noise on deceleration is almost always a bad pinion bearing or really bad preload. The slack lets the pinion go rearward too far. The first question I would have is if the yoke was changed out with the driveshaft replacement? That axle uses a crush sleeve and once used it should be replaced to get the proper bearing preload with a new yoke.

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