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I was on my way home and the transfer case went into neutral. Loud 'bang' then it was stuck in Lo range. This all happened 737 miles from home in Provo UT. Pulled the fill plug and this time there was metallic/black fluid (which I just changed roughly 300 miles ago in Moab). Luckily my father in law (who I was following) towed his TJ to Moab for wheeling, so we loaded my XJ up on the car trailer and used the TJ to tow my camper home to CA.
Gonna split the case open this week. My guess: something was dragging on the low range fork, 80 mph speed with a trailer it finally gave out. The 231 is the only stock component other than the D30. maybe it was a bit much, maybe I didn't rebuild it right 23k ago.
I will post updates with pics of the carnage once I get it apart. Just glad to be home, fun trip but Utah kinda sucked. Good scenery but backward laws that didn't make sense. Kinda glad to live in Cali.
Sorry to hear of your carnage......and I'm glad that you live in CA too! We need less folks moving to UT from CA to escape the high cost of living and Progressive policies, only to complain that UT isn't like CA........ :twak::twak::twak:
Ok pulled it apart today. The high/low range fork was completely cooked and there was aluminum pieces from it stuck in the pump pickup screen. I have been texting Blondjon to figure out the failure mode. So far everything looks ok. My guess is that the nylon bushings fell off or wore out which caused the noise, the heat and ultimately the failure. I took a pic and will post it tomorrow.
I just rebuilt it 23k ago when I put the 27spline input shaft in and the SYE. Gonna replace all the bearings, the seals, the planetary gears, slip gear for high/low and the shift fork. The selector shaft is spot on with no play so gonna leave that alone. The bearings seem all good but after running them in that nasty fluid I don't know. This rig sees 2k mile multi state trips regularly and I don't want to chance it. It's our overland rig. Breaking down 14 hours from home with my 4 year old and 4 week old was no fun, that's part of the adventure though!
The NP231 is the ONLY part on the jeep that is stock (other than the upgrades I did to it) maybe it just can't handle the LS? I don't know? Seems weird to have the nylon bushings fail, I don't want to miss anything......
Didn't mean to offend on the Utah comment, I'm just used to going to the gas station to grab a decent six pack and that was not an option in Utah. It was like a whole ordeal to get good beer.
If I got another case I would prob want to rebuild it as well. It's only like $500 in parts to rebuild mine. If I did go the new case route what's a good source? I would also have to swap over the inner planetary (input shaft) gear so it would mate to my 4l60e trans. It's 27 spline.
I'd be looking into the feasability of a Chevy NP231 variant. They used a wider chain and cogs (but then, that doesn't seem to be what failed) and should bolt right to the 4L60E.
If I got another case I would prob want to rebuild it as well. It's only like $500 in parts to rebuild mine. If I did go the new case route what's a good source? I would also have to swap over the inner planetary (input shaft) gear so it would mate to my 4l60e trans. It's 27 spline.
NP231's don't fail very easy. If it were me, I'd find a decent mileage-ish NP231, crack it open and maybe replace the chain and shift fork pads. If the bearing looked good, I'd leave them.
With that kind of money...thought about looking into a different t-case all together?
Hell, that's halfway to a Rubi case just for the rebuild.
Since you're running an LS, I'd possibly look into something a little more HD.
I'd be looking into the feasability of a Chevy NP231 variant. They used a wider chain and cogs (but then, that doesn't seem to be what failed) and should bolt right to the 4L60E.
So if i don't do the planetary i'm looking at $200 ish (including a new oil pump, rebuild kit, shift fork and low/high slip gear). The planetary is another $200, may skip that since mine still looks decent.
Here is the shift fork:
Slip gear:
This is the input gear i got from advanced adapters and have been running, its 27 spline, still in awesome shape:
Ok pulled it apart today. The high/low range fork was completely cooked and there was aluminum pieces from it stuck in the pump pickup screen. I have been texting Blondjon to figure out the failure mode. So far everything looks ok. My guess is that the nylon bushings fell off or wore out which caused the noise, the heat and ultimately the failure. I took a pic and will post it tomorrow.
I just rebuilt it 23k ago when I put the 27spline input shaft in and the SYE. Gonna replace all the bearings, the seals, the planetary gears, slip gear for high/low and the shift fork. The selector shaft is spot on with no play so gonna leave that alone. The bearings seem all good but after running them in that nasty fluid I don't know. This rig sees 2k mile multi state trips regularly and I don't want to chance it. It's our overland rig. Breaking down 14 hours from home with my 4 year old and 4 week old was no fun, that's part of the adventure though!
The NP231 is the ONLY part on the jeep that is stock (other than the upgrades I did to it) maybe it just can't handle the LS? I don't know? Seems weird to have the nylon bushings fail, I don't want to miss anything......
Didn't mean to offend on the Utah comment, I'm just used to going to the gas station to grab a decent six pack and that was not an option in Utah. It was like a whole ordeal to get good beer.
At the very least, the oil pump needs to be replaced. It may well have been the failure to begin with (I am betting that is the case).. the OP failed, the shift fork nylons melted, the fork gouged the component it contacts (drawing a blank- shift collar?) and frag went throughout the assembly.
New chain if it fails the slack test, new bearings and seals, OP, shift fork and nylons, and inspect everything within an inch of its life. If too much is questionable, consider sourcing another unit and transferring the SYE over. It will likely be a hard call- rebuild or replace the entire unit. I know you can find 231s cheap out here. Maybe time for an upgrade to the Rubi case? Of course an Atlas is always a possibility, but I think if that made much financial sense we'd probably be talking about a built TJ at the very least.
I built everything on the truck, its been in my family since '93 (assuming your talking about mine). It became mine in 2013 when i asked my dad for it (it was sitting in his field growing weeds and full of water). Thats why i want to keep the existing t-case since i know where its been etc...
Also this t-case is really wierd. According the numbers stamped on the side it is an AMC 231.
I was considering an atlas, then my dog ate something so yeah.....
prob hard to tell but the thing is completely disassembled and the parts have been cleaned. I even assembled the t case halves together with the shift fork installed to see if there is play and there was no play.
Honestly, I remember when i rebuilt it i had trouble getting the nylon bushings on the fork. Come to find out this time around that the '87-'88 have a different shift fork. I vaguely remember trying to force the nylon bushings on and they weren't really on right but i ran it anyways. Not doing that again!
From having built rebuilt t-cases & transmissions, I know what a planetary looks like.
My concern would be the bearings and surfaces on the shaft the gears ride on....you can't see them unless you 'break' it apart. I'd also try to see if you can find a 6 pinion planetary to use....would make it handle the V8 much better.
When I rebuilt my last 727, we used planetaries from the cummins auto transmissions to strengthen mine. We were able to double the pinions on all planetaries.
I would at the very least disassemble, clean very carefully, and inspect every precision ground and hardened surface for damage. Any sign of damage? Scrap it.
Make very certain that you clean the oil passages on stuff, they're probably packed with metal filings and globs of plastic.
Bet your fork issue was the root of it... but I'd be real tempted to start with a clean case that you know isn't a pile because it's got clean fluid, install your SYE and input gear and move on with your life.
From having built rebuilt t-cases & transmissions, I know what a planetary looks like.
My concern would be the bearings and surfaces on the shaft the gears ride on....you can't see them unless you 'break' it apart. I'd also try to see if you can find a 6 pinion planetary to use....would make it handle the V8 much better.
When I rebuilt my last 727, we used planetaries from the cummins auto transmissions to strengthen mine. We were able to double the pinions on all planetaries.
Found a np231 on Craigslist for $25. Gonna pick it up tomorrow and salvage stuff out of it, or rebuild it completely with my parts (SYE and upgraded 27 spline input shaft). I may try to make a 6 gear planetary with the planetariums that i will have. And I have a new pump, pickup screen, bearing and seal kit on its way as well as a new shift fork.
Also, may be a bit overkill but i will be drilling and tapping the case for a 220 degree warning light sensor and mounting a warning light next to my trans temp gauge. What are your thoughts on 220? I can do 210 or 230 as well, My guess is anything north of 200 is a bit much.
