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Thread: Transfer Case Swap Info NP249->NP231 & NP242 Reply to Thread
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  Topic Review (Newest First)
Yesterday 05:31 PM
CatSplat FWIW, when I did the 242 swap I used the 249 gate with no issues. Never did bother to install the 242 gate, just put on a 242 bezel.
08-07-2020 08:12 AM
Timo_90xj
Quote:
Originally Posted by terpsmandan View Post
A great solution is a mountain vista linkage swap. The actuator rod on my 249 was too long for the 231 that I swapped in and would rub the driveshaft when engaged.
Z- linkage is not an issue with a 249->242 swap, but it's the metal shifter gate inside the cabin that may run out of travel. So you're missing either RWD or 4lo.

I'm using a Novak cable shifter. I've been very happy in how it works.
08-07-2020 04:57 AM
terpsmandan
Quote:
Originally Posted by Timo_90xj View Post
Quote:
Originally Posted by Gurfen View Post
So, i've searched and searched for info about this, and the way i interpret the info in this thread... a 242 tc from a -98 GC with the I6 should fit "bolt-on" to my -96 GC 5.2 V8 with a 249 tc?

Yeap, direct fit for the TC.

Keep in mind the 249 shifter gate may not provide enough throw to get all the ranges from the 242. Either grab the 242 gate or slightly modify the existing one with an angle grinder.
A great solution is a mountain vista linkage swap. The actuator rod on my 249 was too long for the 231 that I swapped in and would rub the driveshaft when engaged.
08-07-2020 04:55 AM
terpsmandan
Quote:
Originally Posted by Gurfen View Post
So, i've searched and searched for info about this, and the way i interpret the info in this thread... a 242 tc from a -98 GC with the I6 should fit "bolt-on" to my -96 GC 5.2 V8 with a 249 tc?
As far as input shafts and things go, they should be identical, or am i missing something here?

There's just so much info on this subject, it's hard to sort out for my tiny brain... 😖
The only concern, and correct me if I’m wrong, is the slip yoke I remember that the later 242 cases have in external slip yoke and the 249 has in internal slip yoke.
08-07-2020 02:01 AM
Timo_90xj
Quote:
Originally Posted by Gurfen View Post
So, i've searched and searched for info about this, and the way i interpret the info in this thread... a 242 tc from a -98 GC with the I6 should fit "bolt-on" to my -96 GC 5.2 V8 with a 249 tc?

Yeap, direct fit for the TC.

Keep in mind the 249 shifter gate may not provide enough throw to get all the ranges from the 242. Either grab the 242 gate or slightly modify the existing one with an angle grinder.
08-07-2020 12:39 AM
Gurfen So, i've searched and searched for info about this, and the way i interpret the info in this thread... a 242 tc from a -98 GC with the I6 should fit "bolt-on" to my -96 GC 5.2 V8 with a 249 tc?
As far as input shafts and things go, they should be identical, or am i missing something here?

There's just so much info on this subject, it's hard to sort out for my tiny brain... 😖
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.
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