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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
I have a knocking noise from under the seats upon acceleration on my 89xj. It smooths out when throttle is maintained, but come back again when accelerating hard. This surfaced after I installed my 3” lift. everything else is stock accept the upper/lower control arms, track bar, coil springs leaf springs and shocks. I’ve read threads on how motor mounts and the transmission mount can cause this, but they are all new. I’ve also read that u-joints can also cause this same type of noise upon accelerations. My rear driveshaft does has some minimal play at the u-joints when pushing up on the shaft. The front shaft feels pretty solid. Any help will be greatly appreciated.
I’ve also read that u-joints can also cause this same type of noise upon accelerations. My rear driveshaft does has some minimal play at the u-joints when pushing up on the shaft
Then you should start by replacing your joints.
Cheap and easy. Even if it doesn't solve your problem, they need to be changed anyways.
The joints may only be acting up now after the lift because of the different angles they're under.
You may have a worn slider yoke where the driveshaft goes onto the t/case. Now that you have more angle in the driveshaft, it could be running out off center under load. This is especially noticeable if you have a t/case with and external boot on a long shaft. It may be time for an SYE.
You may have a worn slider yoke where the driveshaft goes onto the t/case. Now that you have more angle in the driveshaft, it could be running out off center under load. This is especially noticeable if you have a t/case with and external boot on a long shaft. It may be time for an SYE.
Thank you for your response Dave1123. I’ll will check that out too.
Well, picked up some spicer u-joints today and pulled the rear driveshaft. At some point in this jeeps life it apparently lost the rear driveshaft from the looks of some dents under the rear seat and a small hole. Here is a pic of the end of the shaft. Can I save this dang thing?
I seriously doubt it. A little finesse in a machine shop could probably save it, but not cost effective.
I figured that as well. Thank you for responding so quickly Dave1123. This might be a dumb question, but if I buy a new one or get a used one from JY will they go back in without any problems if I haven’t moved the Jeep and line up the key way ? I see a key way on the internal spline. I guess I’m asking because there is so much emphasis on marking lines on the drive shaft to be sure it goes back in the exact way as it came out on videos and articles I have checked.
JY wanted $150 for a used driveshaft! I don’t know maybe that’s what they go for. Anyways I went by a local 4x4 shop and they were kind enough to go out and search there pile of parts and found me a match for $40.
So, my question is now, does it matter which end the the slip/shaft is attached to my new/used driveshaft? Also, I already have new spicer u-joints and the appear to be exact as the ones I removed from the new/used drive shaft. Is there anything I should check before installing the u-joints? I have no idea what the driveshaft came out of other than it says spicer on it and it is the exact length and match to my old and damaged driveshaft.
05-05-2020, 05:42 PM
Thumping noise under floor pan.
