highlandjeeper Posted November 11, 2008 Share Posted November 11, 2008 Drove 1.5 hrs to go wheelin yesterday with some members of our club only to discover that my t-case is piled up when shifted into 4wd :grrrr: . Last time I wheeled it everything was fine. Perhaps when flat-towing it something happened. I removed the rear drive shaft and put the tcase in 2wd and the tranny in neutral. Anyways, my question is this: Will the t-case or just the internal parts from a 1989 231 that was mated to a Peugot tranny in a YJ swap with my 1991 MJ 231? I think I read somewhere that the clocking is different but can't recall for sure. As for the input, I should be able to swap mine. I haven't disasembled either case yet to compare. I think I may order a Tera 2 Low kit as it is going in for surgery anyways. Link to comment Share on other sites More sharing options...
Motion Offroad Posted November 11, 2008 Share Posted November 11, 2008 TC should of been in (N) and tranny should of been in (D) or (1st) if your flat towing. If the rear DS was not connected unless you have a non-CAD axle you should of been fine. Link to comment Share on other sites More sharing options...
highlandjeeper Posted November 11, 2008 Author Share Posted November 11, 2008 TC should of been in (N) and tranny should of been in (D) or (1st) if your flat towing. If the rear DS was not connected unless you have a non-CAD axle you should of been fine. I have been told that the t-case when shifted into neutral locks the front and rear outputs although the input is in neutral. I have also been told that because there is no detent for neutral, it is a bad idea to do that. Regardless, I plan not to flat tow any more. Just need a trailer. The more important reason for this thread is for swapping info for the t-case, although some good towing info was also needed. Is it the t-case that is clocked different, or is it the tranny flange that is different between XJs and YJs? Link to comment Share on other sites More sharing options...
Pete M Posted November 11, 2008 Share Posted November 11, 2008 I removed the rear drive shaft and put the tcase in 2wd and the tranny in neutral. After removing the rear driveshaft you did plug or cap the back of the t-case, yes? Link to comment Share on other sites More sharing options...
highlandjeeper Posted November 11, 2008 Author Share Posted November 11, 2008 I removed the rear drive shaft and put the tcase in 2wd and the tranny in neutral. After removing the rear driveshaft you did plug or cap the back of the t-case, yes? I had a spare yoke that I put in place. Link to comment Share on other sites More sharing options...
Pete M Posted November 11, 2008 Share Posted November 11, 2008 Oh good. :D We can check "no fluid" off the list of possibly problems. The clocking differences should be in the transmission, so the t-cases would be swappable. But the input spline count of the YJ case should be 21, so be prepared. Link to comment Share on other sites More sharing options...
Eagle Posted November 11, 2008 Share Posted November 11, 2008 The older transfer case is a 21-spline. Your '91 has 23 splines. That means the input shafts are definitely not the same. I have no idea whether or not things like bearings are interchangeable. Link to comment Share on other sites More sharing options...
reson46 Posted November 11, 2008 Share Posted November 11, 2008 I have some thoughts about what may have happened to your transfer case. Your MJ is a '91? Didn't they eliminate the vacuum CAD this year? Does your's have the vacuum CAD? If it does not have the vacuum CAD, that would mean the front driveshaft and transfer case output were turning when you flat towed. The transfer case oil pump runs off the rear output shaft. With the rear driveshaft disconnected and the transfer case in 2WD, the pump will not be running and oil will not be circulating through the transfer case. I am guessing the bearings the front output shaft ride in may have become oil starved when you flat towed. Sound plausible to anybody else? :hmm: Willy Link to comment Share on other sites More sharing options...
Lewt2007 Posted November 11, 2008 Share Posted November 11, 2008 that could happen due to lack of oil on the bearings and gear set Link to comment Share on other sites More sharing options...
DirtyComanche Posted November 11, 2008 Share Posted November 11, 2008 I have some thoughts about what may have happened to your transfer case. Your MJ is a '91? Didn't they eliminate the vacuum CAD this year? Does your's have the vacuum CAD? If it does not have the vacuum CAD, that would mean the front driveshaft and transfer case output were turning when you flat towed. The transfer case oil pump runs off the rear output shaft. With the rear driveshaft disconnected and the transfer case in 2WD, the pump will not be running and oil will not be circulating through the transfer case. I am guessing the bearings the front output shaft ride in may have become oil starved when you flat towed. Sound plausible to anybody else? :hmm: Willy You are correct. Or so I would assume. It was my first thought when I read the OP. However, the bearings for the front output are oil bath lubricated. It's more likely that something nasty happened up in the area of the mainshaft as the chain/sprocket would still be turning on it without oil. I wanna see a disection. Link to comment Share on other sites More sharing options...
Pete M Posted November 11, 2008 Share Posted November 11, 2008 All MJs had the CAD (except for a few rare 86s). Link to comment Share on other sites More sharing options...
highlandjeeper Posted November 12, 2008 Author Share Posted November 12, 2008 All MJs had the CAD (except for a few rare 86s). Mine does not have CAD. I am unsure what the PO swapped the front axle out of when he did most of the convert to 4WD. As for the input, I will disassemble the donor t-case tomorrow and hopefully this weekend I can remove the bad one and see if the input will directly swap. Once the truck is back up and running I will send the old one to the morgue for autopsy and post some pics. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted November 12, 2008 Share Posted November 12, 2008 All MJs had the CAD (except for a few rare 86s). from 1991 on for sure, the only jeeps with CAD were YJ's. this may continue to mid 1990, but I am unsure. having a non-CAD axle is commonly associated with having an np242, which MJ's never came with from factory. Chrysler decided that the CAD wasn't doing any good and so they deleted them. perhaps this is what you were thinking. Link to comment Share on other sites More sharing options...
KillerCOM Posted November 12, 2008 Share Posted November 12, 2008 definitely messed something up on the main-shaft. you're supposed to the leave the DS in when flat towing, put the transmission in gear, and the t-case in neutral. Link to comment Share on other sites More sharing options...
BLHTAZ Posted November 12, 2008 Share Posted November 12, 2008 definitely messed something up on the main-shaft. you're supposed to the leave the DS in when flat towing, put the transmission in gear, and the t-case in neutral.Yep...that configuration allows it to roll and keeps the oil pump working in the t-case. Sounds like whom ever told you how to flat tow did you wrong and deserves a... :thwak: Link to comment Share on other sites More sharing options...
JeepcoMJ Posted November 12, 2008 Share Posted November 12, 2008 I remove both driveshafts while towing. it takes time, but not enough to make me not want to do it. that way nothing moves. Link to comment Share on other sites More sharing options...
highlandjeeper Posted November 13, 2008 Author Share Posted November 13, 2008 definitely messed something up on the main-shaft. you're supposed to the leave the DS in when flat towing, put the transmission in gear, and the t-case in neutral.Yep...that configuration allows it to roll and keeps the oil pump working in the t-case. Sounds like whom ever told you how to flat tow did you wrong and deserves a... :thwak: He said that was what the manual from his TJ instructed. I originally towed with both DS's removed and was told that I didn't have to remove the front one. :dunno: Anyways, the repair should cost me under $100 and a little time as I got another t-case for $50. I disassembled it tonight and everything looks tip-top inside. Now all I have to do is remove the bad one and disassemble it for the input gear (if it isn't damaged) and install it in the new one. Piece of cake. As for the Tera 2 Low kit, it is a few weeks away, so I will not be putting one in :( Link to comment Share on other sites More sharing options...
reson46 Posted November 13, 2008 Share Posted November 13, 2008 He said that was what the manual from his TJ instructed. I originally towed with both DS's removed and was told that I didn't have to remove the front one. :dunno: You may suggest to him to take another look at his manual before this happens to him. I can just about guarantee that is not what is in his manual. Willy Link to comment Share on other sites More sharing options...
Pete M Posted November 13, 2008 Share Posted November 13, 2008 A TJ t-case is a little different internally than an MJ t-case. The towing procedures that work for one may not work for the other. Link to comment Share on other sites More sharing options...
reson46 Posted November 13, 2008 Share Posted November 13, 2008 A TJ t-case is a little different internally than an MJ t-case. The towing procedures that work for one may not work for the other. Unless it's a Rubicon, it still has a 231 transfer case. Every TJ 231 I've opened up has the oil pump running off the main shaft just like an MJ 231 which would result in the same problems. I realize different rear output housings were used on TJ 231s, but I don't think that would change the flat towing procedures. Willy Link to comment Share on other sites More sharing options...
KillerCOM Posted November 16, 2008 Share Posted November 16, 2008 :agree: you're correct all NP 231J's are mechanically the same. towing procedures are the same between vehicles with that tcase. Link to comment Share on other sites More sharing options...
mvusse Posted November 16, 2008 Share Posted November 16, 2008 My 87 Comanche owner's manual (with 231), flat towing instructions: Recreational Towing (Behind Motorhome, etc.) 1. Shift transfer case to 2H and check that the 4wd light goes out. 2. Drive vehicle 10 ft. rearward and then 10 ft. forward to make sure the axle is disengaged. 3. Shift transmission to neutral. 4. Turn off the engine with the ignition key in the unlocked off position. 5. Shift the transfer case lever from 2H to N (Neutral) position. 6. Shift manual transmission into gear or automatic transmission into Park. 7. Attach vehicle to the tow vehicle with tow bar. This means transmission in Park, transfer case in Neutral, front axle disengaged, both drive shafts in place. Link to comment Share on other sites More sharing options...
highlandjeeper Posted November 16, 2008 Author Share Posted November 16, 2008 Picked up another 23 spline input gear from the wreckers yesterday. Now I can raessemble the new t-case and be ready to just swap it in when the old one comes out. I also don't have to rely on the parts I needed from the old one to be good. I am still going to tear into it to diagnos what happened. Link to comment Share on other sites More sharing options...
highlandjeeper Posted November 23, 2008 Author Share Posted November 23, 2008 Got the new t-case installed last night. I also disassembled the old one. Can you spot the problem? Image Not Found I wouldn't have expected that to happen so suddenly. Worked fine on the last trip and then the next time out was extremely bad :dunno: Link to comment Share on other sites More sharing options...
DirtyComanche Posted November 23, 2008 Share Posted November 23, 2008 Anything else screwy in it? Is the casing all beat up from the chain? Link to comment Share on other sites More sharing options...
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