Cliff Travis

I have a 1992 Cherokee Sport, automatic, np231 with 8.25 rear. It is completely stock. The original leaf spings were sagging quite a bit. I recently replaced the rear leaf springs with Dorman stock replacement springs. Everything went smooth. I got all of the bolts out without too much difficulty. I gained about 1.5" over the old springs. The only problem is now whenever I go over big bumps or brake and make the front end dive, I get an awful clunking sound and vibration.
I have traced down the problem: when the rear end lifts up, the slip yoke and front u joint are binding. I am at a loss as to how to fix this. I suspect the problem was already there but I never knew it due to the old springs sagging so much. I took out the drive shaft today and cleaned/inspected the u joints. I gridded down some material on the drive shaft where it is contacting but it was not enough. It is quite significant the amount it contacts, something is not right. Now I notice that the slip yoke is also sticking out too far. The transfer case has a bunch of gasket material sticking out of the mating surfaces. It looks like a previous owner may have opened up the transfer case. Maybe they put in wrong replacement parts? The slip yoke looks to be the correct one for my year. Is it possible to need to shim the rear axle on stock suspension? Any ideas would be appreciated.

Cliff Travis

Im thinking my driveshaft is too short. I measured 29 5/8" center of u joint to center of u joint. It looks like there are a couple different stock driveshaft lengths, depending on the year, motor/transmission, tcase and rear end. I have been searching around and cannot find the answer.
If anybody has a pre 95, 4.0L auto, NP231 t-case and Chysler 8.25 rear end would you do me a huge solid and measure your rear driveshaft length.

Basslicks

I was just about to say that. My '92 has an AW4 w/ np231, but has a Dana 35.... I'm also lifted 3.5" in the rear and don't have any vibes. I'll try to remember to measure on my lunch in a couple hours to see if that will help you at all.

Seems like that's way too short though regardless. Try taking a measurement from the main eyes to the centering pin on the old AND new leafs and see if maybe the new leafs are different. If so, you may be able to find a shop that specializes in leaf springs and see if they can drill a new hole.

Cliff Travis

Thank you Basslicks for that idea, if the centering pin was further back on the new leafs that would cause the ds to be short.

I just compared the old leaf springs to the new ones and the centering pin is in the same location.

Looking at my transfer case, it definitely looks like someone has removed/replaced the rear housing extension. Im guessing that whatever the issue was, whoever fixed it put in the wrong drive shaft. Currently I cannot find any used ds online that fit all the same specs as my vehicle. There are a ton of used drive shafts for 96-01 but that is not gonna work. I see Tom Wood's make OEM replacement driveshafts for $219. Think I'm gonna bite the bullet and order one so I can get my rig back on the road.

Basslicks

CRAP! I forgot to measure mine, man.

Why wouldn't the 96-01 work? the distance between the pinion yoke and output didn't change, just the style of the tail shaft.

Cliff Travis

I was thinking it wouldn't work because the 96-2001 had the updated transfer case like the picture below. It doesn't have the rear housing extension mine does and the slip yoke is a different part number. Also I would think most 96+ would have ABS and thus have D35 rear end = different length pinion yoke?



It very well could use the same length driveshaft but when I see different part numbers it make me nervous that it wont fit. My Jeep has been down for several months. I took my old leaf springs off the day before the replacements were supposed to be delivered. One of the leaf springs ended up getting lost in shipment. So while I was waiting for the replacement to come in I preceded to crash my dirtbike, requiring surgery/cast. I'm finally able to work on my vehicle again and just want it drivable. For $235 Im getting a completely new drive shaft, balanced and new u joints and straps from Mr Tom Wood shipped to my door by Monday.

I hope this fixes the problem. I will update when new ds installed.