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  Topic Review (Newest First)
06-28-2020 08:08 PM
JAF_98_ZJ I just finished up with a 249 to 242 tc swap and joined the forum just because of this info on this thread! I'm glad I found it before I was to far along! I was having an issue with the gear cut difference on the planetary/input shaft. I put the 249 input into the 242 planetary. It seems clunky, not smooth...I stopped to do some research and found this thread....THANK YOU!
06-24-2020 02:00 PM
wildbill23c
Quote:
Originally Posted by variable View Post
I'm pretty sure I was observing the differential being a differential and for some reason was expecting it to behave differently - I wasn't thinking about the fact that I had the drive shafts removed. But I did notice that the shift fork and spring assembly weren't all entirely square, so I coaxed them back into shape and things are behaving much nicer now. I think though that the low range fork - the one that's cast and not a bent piece of steel (not sure why they did that) may have a slight bend in it as well that I didn't notice as going from 4Low to Neutral in the t-case leaves me stuck unless I really want to grind the gears or turn the car off (I chose the later), then I can put it into gear again (that included going back into 4Low).

I can live with that one - its just an inconvenience at the moment (more so off road I'm sure, but beats tearing it apart yet again... ATF isn't cheap!)

Now to track down why my driveline still has vibes in it even though the pinions are almost dead on (with in 0.2* at the rear, less in the front).. I'll save that for the appropriate thread though.
Typically when shifting to low range you would be rolling a few mph while shifting which may be why it wouldn't go into low range or why its difficult to engage it.
06-23-2020 10:57 PM
variable
Quote:
Originally Posted by wildbill23c View Post
I don't think you can physically put the case together and have it spinning wrong, its chain driven, so it'll spin the same way, and I don't think there's any way it could go together backwards to get it to spin opposite directions mechanically.
I'm pretty sure I was observing the differential being a differential and for some reason was expecting it to behave differently - I wasn't thinking about the fact that I had the drive shafts removed. But I did notice that the shift fork and spring assembly weren't all entirely square, so I coaxed them back into shape and things are behaving much nicer now. I think though that the low range fork - the one that's cast and not a bent piece of steel (not sure why they did that) may have a slight bend in it as well that I didn't notice as going from 4Low to Neutral in the t-case leaves me stuck unless I really want to grind the gears or turn the car off (I chose the later), then I can put it into gear again (that included going back into 4Low).

I can live with that one - its just an inconvenience at the moment (more so off road I'm sure, but beats tearing it apart yet again... ATF isn't cheap!)

Now to track down why my driveline still has vibes in it even though the pinions are almost dead on (with in 0.2* at the rear, less in the front).. I'll save that for the appropriate thread though.
06-23-2020 07:56 PM
wildbill23c Could be the transfer case was stuck in full time, so when you shifted it to part time high and low it hadn't disengaged from the full time mode? I know it can happen in high range between full and part time, so may be what happened was it was just stuck in full time, I know with my 98 ZJ between part time and full time it'll get stuck in part time quite often when I want full time mode, it takes a bit sometimes shifting out of 4WD and back to full time mode a time or 2 in order to get it to shift to full time mode...mostly due to lack of use I think. I don't think it could get stuck in full time and be engaged in low range as its running through the low range reduction gears at that point, but pretty sure it may have just got stuck in between full and part time and was making you think something was wrong.

I don't think you can physically put the case together and have it spinning wrong, its chain driven, so it'll spin the same way, and I don't think there's any way it could go together backwards to get it to spin opposite directions mechanically.
06-23-2020 07:23 PM
variable Yeah..... that occurred to me somewhere in the middle of the night while I was sleeping and I think I face palmed in my sleep... and you beat me to it. Oh well

However... what it doesn't explain is why I was essentially getting 4FT in all but neutral.

I tore it all down again and found that the low range planetary gear "box" must have some very minor change at some point - I had another one that was almost identical (even had the same number stamped on it - 549 I think?) - the main shaft in the one I was using sat about a snap ring's width too deep (no I wasn't missing any). I swapped the other one in though I didn't know yet that there was going to be a difference till I put it back together to the point where I could stick something flat across the front and rear output gear, and low and behold, that fixed the shaft sliding in and out problem. I then noticed that the gear that slides into the differential 'box' wasn't always in all the way when it was in neutral so I took a close look at the shift fork and found it to be a little bent - not a lot, but enough apparently.

In any case, aside from some weirdness with getting out of 4 low, so far so good. Need to freeway test it next. I doubt this is going to solve my vibrations, but hopefully it'll be one less thing to deal with. (My back would really appreciate it...)
06-23-2020 01:13 AM
Timo_90xj
Quote:
Originally Posted by CatSplat View Post
If the 242 is in 4FT and you rotate the input with nothing connected to the outputs, the outputs will rotate in opposite directions due to the open center differential.
^- This.

I currently have my 242 disassembled in the garage floor, and it is not possible to assemble it so that front and rear outputs would rotate in different direction when in 4 hi/lo part time.
06-22-2020 03:10 PM
CatSplat
Quote:
Originally Posted by variable View Post
I was pretty sure it couldn't happen either... Granted I was doin this with my hand, but they were most definitely spinning in opposite directions - should have taken a video. I haven't been able to reproduce it and I'm not going to mount it up again till I've got things working again. It wasn't just 'kind of' spinning with, I couldn't spin one and stop the other with my hand. :Shrug:

If the 242 is in 4FT and you rotate the input with nothing connected to the outputs, the outputs will rotate in opposite directions due to the open center differential.
06-21-2020 10:19 AM
variable
Quote:
Originally Posted by Timo_90xj View Post
I am actually pretty sure that cannot happen, because the front axle output is coupled to mainshaft, so it must rotate in the same direction.
I was pretty sure it couldn't happen either... Granted I was doin this with my hand, but they were most definitely spinning in opposite directions - should have taken a video. I haven't been able to reproduce it and I'm not going to mount it up again till I've got things working again. It wasn't just 'kind of' spinning with, I couldn't spin one and stop the other with my hand. :Shrug:
06-21-2020 05:47 AM
Timo_90xj I am actually pretty sure that cannot happen, because the front axle output is coupled to mainshaft, so it must rotate in the same direction.
06-20-2020 08:43 PM
variable How awesome is this: my dumb *** managed to put my t-case back together (249/242) in such a way that if I hadn't caught it when hooking up the shift linkage, I would have ended up with the front wheels and the rear wheels spinning in opposite directions... FML Got the whole thing put back together and mounted back up.. I must have been really f*cking distracted... I can't believe it even went back together without issue.

The hell did I do???!

Only one gear actually appears to engage with the transmission, the rest appear to be part time or 4low - not sure which with it mounted. Neutral works fine... but can't get it into where 4low would have been. My back already hates me as it is.. (imagine lots of cursing going on right now)
06-15-2020 11:19 PM
variable Any idea what might cause a 249->242 converted t-case to slip out of full time 4wd? I've been having a boat load of issues that I didn't think were related to the t-case (primarily vibrations) but unless black is white, cats are dogs and I'm lysdexic, I've got those diffs dialed in about as close as they're gonna get. (this also has a hack n tap SYE FYI)

I did have an issue where the output yoke to the rear end had some in and out play - it'd been this way for well over a year I think (since I installed it). Fixed that today when I realized I'd been missing a snap ring at the rear shaft, but between that and trying to narrow down the vibrations - drove without the front drive shaft, no dice, drove around without the rear drive shaft, no dice, and I think this is where my problems really started as I had a hard time getting it into part time 4wd... 2wd pretty much disappeared completely... haven't changed the linkage, but I guess thats something to play with, but I don't think that would account for the vibes. I can't imagine BOTH drive shafts have some balancing issue either, one of them is relatively new and they all have new u-joints. Even replaced the front rotors on a slim chance from a different thread (was on my to do list anyway).

Assuming the shift issue is unrelated to the vibration, is "driveline" vibration potentially a symptom of something borked in the t-case? I'm pretty sure I'm going to be tearing apart the t-case soon as a result of all this but between having a small one car garage, having to hunt for a new job and surprise back pain (f*ck getting old)...
05-05-2020 08:36 AM
CatSplat
Quote:
Originally Posted by PolkaPower View Post
I measured it at the junkyard and it was a direct fit after the yoke swap so...
Now that I look back on my thread from years ago it was 31 inches.

Sent from my BND-L24 using Tapatalk

Yeah I'm not saying it wouldn't fit your late V8, it's definitely close enough. It's too short for an early V8 though.
05-04-2020 10:51 PM
PolkaPower
Quote:
Originally Posted by CatSplat View Post
'96 4.0 is 31.770" - closer, but not likely long enough for an early V8 - it would be pretty close to maxed out at ride height.







30.530" for a '93 4.0L. They are noticeably shorter than the early V8 shafts due to the 42RE being shorter than the 46RH. Shorter than the late 4.0L shafts due to the long-pinion D30, too.
I measured it at the junkyard and it was a direct fit after the yoke swap so...
Now that I look back on my thread from years ago it was 31 inches.

Sent from my BND-L24 using Tapatalk
05-04-2020 10:36 PM
CatSplat
Quote:
Originally Posted by 1996maroonzjf View Post
Looks like he can get away with a 96 4.0 w/ 242 shaft at 33.00 inches. They are u-joint to u-joint and might be easier to find.

'96 4.0 is 31.770" - closer, but not likely long enough for an early V8 - it would be pretty close to maxed out at ride height.




Quote:
Originally Posted by PolkaPower View Post
I used a front shaft from a 93 4.0 in my 5.9. Was around 34" if I remember. It was maybe 30 bucks from the pick and pull.

30.530" for a '93 4.0L. They are noticeably shorter than the early V8 shafts due to the 42RE being shorter than the 46RH. Shorter than the late 4.0L shafts due to the long-pinion D30, too.
05-04-2020 09:53 PM
PolkaPower
Quote:
Originally Posted by 1996maroonzjf View Post
Looks like he can get away with a 96 4.0 w/ 242 shaft at 33.00 inches. They are u-joint to u-joint and might be easier to find.
I used a front shaft from a 93 4.0 in my 5.9. Was around 34" if I remember. It was maybe 30 bucks from the pick and pull.

Sent from my BND-L24 using Tapatalk
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