zedpapa

I will be converting my 89 to 4x4 soon and have the option of using a 231 or a 242. as i plan to move to an area where there is snow, i was thinking of using the 242 for the full time option. what are your thoughts on this?

next is my dad gave me a np241c transfer case from a 89-98 tahoe/suburban. according to the research i have done, this is just a full size version of the 231. i have heard that you can swap the larger gears and chain into a jeep case to make it stronger. can i use this 241C for a donor or should i look for different one?

thanks for the help.

zedpapa

5-90

New Venture Gear transfer cases all use the old D300 mounting pattern - if you can get a 21-sp input gear for the NP241, and it will physically fit, just drop that in instead.

The NP242 isn't a bad case, but it can be difficult to do conversions in. The "wide chain" mod is usually done in the NP231 (using NP231C or NP231D parts) vice the NP242. Although, I do understand your wanting a full-time mode (if I can't nail down a 23-sp D300, I'll convert one of the NP242s I have to 23-sp and put it in behind my AX-15 as part of a refit. Ideally, I'd like to do the NV3550/D300 with a twin stick setup, but that's just me. The AX-15/NP242 is perfectly acceptable for my needs.)

I don't know if you'll need to make a new rear driveshaft for the NP241C to fit in your mid-size, you'll probably have to measure that out.

Oh - and if the NP241C has a fixed rear output yoke, that's reason enough to make it fit in place of the NP242 (unless the sheetmetal work you'd have to do is just stupid.) NP242s require some creativity to go SYE - and an SYE is a good idea on just about anything.

zedpapa

thanks for the info. i have an ax-15 to put in with the conversion so i will need the 23-spline setup. and i'm not set on doing any particular upgrade, i'm just trying not to miss anything along the way. as i am at 3" of lift now and plan to go to 4.5-5" soon, a SYE and drive shafts are already planned on.

also, i don't know if i want to "make" anything fit, although i can. i don't ever plan to wheel really hard, but i don't want to break anything either. this is my daily driver and needs to remain reliable.

zedpapa

5-90

Count the splines on the input gear for your NP241C. If they number 23, it should fit (most later automotive apps use a diametral pitch of 24 on splines as a standard. Not all of them - but enough to matter.)

If you don't have a 23-sp input, start by asking at Novak to see if they have - or can make - one for you. Check them out - www.novak-adapt.com. They've got a good Tech archive, and they've got a lot of good conversion parts (I plan to use one of their shifters for the tcase if I stick to the AX-15e/NP242 plan I've currently got in place. If I get the NV3550/D300 I want, all bets are off! I'd prefer a D300 just to get rid of the drive chain, but I can get more 4WD options as well (4WD/HI, 4WD/LO, RWD/HI, RWD/LO, FWD/HI, FWD/LO) using a twin-stick kit.

Off Road Wag

so i have to replace my transfer case but was wondering about the 231 one and other transfer cases. I have a 242 now but was wondering what other kinds i can fit on my 89. Is the 242 good or is there better i can fit. Also it sounded like the 231 doesnt have fulltime by what the guy said? Is that right?

5-90

NP231 = 2HI/4HI(PT)/N/4LO
NP242 = 2HI/4HI(FT)/4HI(PT)/N/4LO

What do you need? What do you do? There are times a question needs to be answered with a question - like now, when you're looking for an answer to an incompleat question.

The NP242, IIRC, actually has a nominally higher torque input rating than the NP231, so there's an advantage there. However, there are more aftermarket upgrades available for the NP231.

So, which do you need? Depends on what you're trying to do? You're actually probably fine with the NP242, but we'd need more information to be sure. Just asking "which one is better?" will generall get you a number of answers - all of which will be totally useless.