Stop-Bump issue on pre-96's?

[S-FLY1]

I have what appears to be a stop-bump issue on my '94 xj. I read that the slip-yokes were self-lubricated from the t-case fluid in the pre-1996 models. Has anyone else had this problem from a pre-1996?

Thanks in advance.

 

[cal]

You didnt actually tell us what the problem you are having is..?

 

[S-FLY1]

"Stop-bump". Basically the symptoms of the same problem that affect the newer XJ's and ZJ/WJ's where the slip yoke gets bound up from the grease drying and when the vehicle comes to a stop, a forward jerking clunk is heard/felt from the rear end and when starting from a complete stop another clunk is heard/felt.

The pre-1996 models are supposed to have a self-lubricating slip-yoke which gets lubricated by the t-case, so I was wondering if it's still possible to have stop-bump in this type of slip-yoke system and if anyone has ever experienced it.

 

[cal]

You have some other problem.

Check for bad ujoints?

 

[S-FLY1]

Yup, U-joints and motor mount/tranny mounts are fine. Checked the brakes as well, all fine. I did notice the slip-yoke seal was worn and not even touching the shaft which makes me think it's this stop-bump issue.

 

[cal]

Yup, U-joints and motor mount/tranny mounts are fine. Checked the brakes as well, all fine. I did notice the slip-yoke seal was worn and not even touching the shaft which makes me think it's this stop-bump issue.

I think your t-case would run dry and fail before you had problems with the slipyoke sticking to the shaft.

 

[S-FLY1]

Anyone else have any ideas/experience? :huh:

 

[89xj]

Anyone else have any ideas/experience? :huh:

since the slip yoke seal is bad, you need to check the level of the transfercase fluid because your leaking atf from the seal. if you dont see atf leaking from the seal, your very low on fluid in the transfercase.

you need to replace the seal and check the fluid level in the transfercase.

 

[S-FLY1]

Sounds good, I'll check that next. I'll report back after I check the level.. Thanks!

 

[RCP Phx]

In 50yrs Ive never heard of "stop/bump",but it sounds like u-joints.Have you actually taken them apart and checked them.You cant always tell just by "feel".

 

[89xj]

x3 on ujoints.

 

[S-FLY1]

In 50yrs Ive never heard of "stop/bump",but it sounds like u-joints.Have you actually taken them apart and checked them.You cant always tell just by "feel".

Here's the service bulletin for the WJ's which describes stop-bump. There was a TSB for XJ's too that I read, but I can't find it at the moment:

030400 - INTERMITTENT BUMP FELT AFTER VEHICLE HAS COME TO A FULL STOP
Date: 06/23/00 (supercedes 030799 dated 10/29/99)

Model year(s): 1999-2000

Description: A condition may exist where the vehicles owner may feel an intermittent bump (stop-bump) once the vehicle is brought to a full stop. The repair technician may erroneously diagnose this condition as a delayed transmission down shift into first gear. This condition may occur 3 to 20 seconds following the stop or when the load on the rear driveline is reduced (e.g., when the applied brake pressure is decreased). The stop-bump condition may be the result of a binding between the splined surfaces of the rear propeller shaft slip yoke and the rear output shaft of either the transfer case or the transmission. As load on the driveline is reduced, the bound slip yoke will release suddenly causing a bump-like sensation. The condition may be intermittent. If the above condition has been experienced, then perform the Repair Procedure. The splined surfaces on the slip yoke section of the new propeller shaft are nickel coated to reduce the opportunity of binding.

Details: THIS BULLETIN APPLIES TO VEHICLES BUILT BEFORE SEPTEMBER 20,1999. A WJ EQUIPPED WITH A 4.0L ENGINE, A NV242 TRANSFER CASE, AND A 198 RBI (M35) REAR AXLE USES A DIFFERENT STYLE REAR PROPELLER SHAFT THAN THOSE WHICH ARE ADDRESSED IN THIS TECHNICAL SERVICE BULLETIN. FOR THIS VEHICLE, THE SPLINED SURFACES ON THE PROPELLER SHAFT SLIP YOKE AND THE TRANSFER CASE OUTPUT SHAFT ARE GREASED TO PREVENT A BINDING CONDITION AND DO NOT REQUIRE REPLACEMENT.

 

[Blaine B.]

How have you checked the driveshaft ujoints? If you leave it in park there will be tension/preload on the ujoints and even if they have excessive play they will feel tight.

Put it in neutral, pull the ebrake, and chalk the wheels; then go under and feel for play.

 

[S-FLY1]

That's actually exactly how we checked.

 

[89xj]

That's actually exactly how we checked.

did you checked the fluid level of the transfercase? if the seal is as bad as you said it was, you should see atf leaking from the slip yoke.

 

[S-FLY1]

Tried to check last night, didn't have a socket large enough. I'll do it today. Also, by atf, I assume you mean 80w90?

 

[89xj]

Tried to check last night, didn't have a socket large enough. I'll do it today. Also, by atf, I assume you mean 80w90?

transfercase takes dexron/mercon II

 

[S-FLY1]

I checked the fluid and topped it up. It was down 1/4 of a quart. The clunk is still there, but I'm almost thinking it's suspension now because when my 200lbs friend got in the passenger seat to help me diagnose the issue, it didn't do it once. I'm lost.

 

[Blaine B.]

I can't see why a person sitting in the passenger seat will stop a bushing from clunking.

Although it will lower the body more and will give the driveshafts less of an angle. Have you greased both slipjoints? The greast the rear stock slipjoint you have to pull the driveshaft out of the tcase....

The front you can just pump some grease into the driveshaft slipjoint zerk fitting.

 

[93gc40]

Did you put ATF into the Transfer case or 80-90, you need transmission fluid? 80-90 would probably stop the noice, but wont do good things for the trnsfer case its-self.Take another look at the U-Joints.