'04 Grand Cherokee Lurch on Stop...

I recently had the bump/stop problem fixed on an '04 JGC 4.0/Selectrac I bought used and so far so good. The TSB summary I saw on the KJ website applies to V8 models and talks about replacing the driveshaft but it also contains a Note that on 4.0's the splines should be greased. The service writer I talked to said it was very common, doesn't hurt anything, and might come back eventually. They pulled the driveshaft and greased it in about half an hour. Mine is still under the 3/36 warranty so I don't know if the powertrain warranty covers it.

Mine would only do it after a delay or on acceleration after very gentle stops, most of the time it happened as the rear end settled right at the end of a stop. One way to confirm it's the driveshaft is put it in neutral before you stop and see if it goes away. The service writer told me a similar problem is sometimes caused by a bad ball joint between the upper control arm and the top of the differential.

Also FWIW, there's a TSB > Hi all,

I am having the exact same issue on an 05 Wrangler 4.0. Here is my little story - took it down to Hoosier National Forest for some off roading. next day I noticed my air conditioner wouldn't switch from blowing all defrost to my feet or face, no changes at all. I took a look under the hood and noticed a tube running to the AC was disconnected from the engine. I replaced the hose and the AC worked fine. The next time I drove the Jeep, I noticed this engine surge. It happens only at a full stop, and when the engine gets to about 700 or 800 RPM, it quickly jumps to about 1500 and the calms down. If I go back under the hood and disconnect that hose again from the engine, there is no more surge. Also, if I run the AC on max/recycle air, it happens, but very very very little, almost would even notice.

I had a 97 Cherokee 4.0 and an 05 GC Hemi - never had any issues with either of those vehicles.

The bump/stop I was experiencing & mentioned in the TSB feels like someone ran into you from behind at a stop light and sometimes sounds like a thump coming from the rear end. There's no rpm surge associated with it. It's caused by the slip yoke binding, then releasing abruptly as the rear end of the vehicle settles either at the end of a stop or on acceleration after a stop. On off the wall guess why older GC's don't do it would be the WJ's front to rear ride height appears to be higher, which increases the driveshaft angle at the slip yoke. Either that or the softer suspension allows more movement, or maybe both.

Hi all,

Just wanted to thank all of you for your help with my "bump stop" problem. I brought it back to the dealer (it was under a 30-day warranty), who told me that nothing was wrong, but decided to grease the rear driveshaft slip yoke splines myself. Fixed the problem.

Thanks much, Tom

thanks for letting us know.

Dave Milne, Scotland

What type of grease did you use?

tw

snipped-for-privacy@gersic.com wrote:

Mobil 1 Synthetic Grease

Same chassis grease you shoot the rest of a Real Jeep with:

Unfortunately there aren't any grease zerks on the driveshaft, so it was more of a "smear" rather than a "shoot"...

Bill, but I don't see your posts unless someone replies with your content pasted as done above, partially. Sorry, but that's the way it's gotta be.

tw

Then repack them with normal lubrication, every six months, and that includes other places where Real Jeeps have zerks like you door hinges. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com

I'm rather hoping I don't have to remove the rear drive shaft every six months...

Only if you take it off road, or pull a trailer. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com

That shaft should be a one time lube, or unless you take it off again for another reason. I was just wondering if you used wheel bearing grease or general lube grease. General lube would make sense since it's not a high friction area like a wheel bearing.

My XJ has experienced the same clunky movement on starts and stops occasionally. I was thinking it might have something to do with the block lift on the leafs since I've never used them before, but I may be pulling my DS soon for a shaft lube.

tw

It was a fairly easy job. Mine was held in by 4 bolts at the rear differential.

Yup, I just would not have considered lubing the shaft to be the fix to this movement, but I'd be happy for this to be the fix. Thanks for the report.

tw

As a follow up to a follow up, I tried this procedure and my 'bump' in the XJ drive train went away. Smooth starts and stops now. Cheap fix, too. Thanks everyone.

tw

snipped-for-privacy@gersic.com wrote: