as long as its out of a 87-90 it will be fine, other than that I think it just bolts up.

 

well its gotta be the transfer case. i pulled open the axel like in your write up and the previous owner already locked it in. when we pulled the cover off the transfer case the oil in it was like a greyish black and around the edges there were slashes were the chain had obviously been slapping against it. dont know if its just kicking off the gears or if its wore out. either way its a safe bet that its the tcase so i need a new one. this guy locally has a 242. guess im going to buy that as long as its a direct bolt up

 

make sure its from a 87-90 (could be 91 also, but thats not as safe of a bet). 91+ has 23 spline input, renix's have 21.

 

so as long as its from a 87-90 it will be a direct bolt? so what the difference between the 231 and 242

 

should be, never done it myself. I think you need the shifter/linkage and shift bezel. Since your vac disconnect is already locked over you dont have to worry about the vacuum lines. (unless you want your 4wd light to work)

242 has full time 4wd, thats about the only difference.

 

I remember reading somewhere that 242's have a low range ratio of 4:1, whereas the 231 has like a 2:1 low.

4:1 is good for rock crawling & such, but not real good for a mudder. They need to go fast.

 

I think it is 2.72:1 low range like the 231. I believe the only xfer case to have the 4:1 ratio is the one found in the Wrangler Rubicon. (I think)

OP: I hope that the 242 works out for you. Transfer case repair/replacement can be expensive. Keep us posted, and take some pictures for us!

 

the 242 and 231 both have the same 2.72:1 low range. the difference in the two is the 242 case has a center differential inside the case which allows it to have full time 4wd, whereas the 231 is only a part time case.

 

so how is it possible to run a 242 instead of a 231? 231 is 2wd-4hi-n-4lo on the lever. if the 242 is different by having 4wd full time that wont make sense. please help so i can find a dif. are they stamped somewhere so i know what im getting too?

 

ok so i found a np231 out of a cherokee locally today. not sure what year. does it make a difference? which would you guys recommend? 242 or 231. i seen a thread that the 231 is better.

 

My 99 xj doesn't like to lock in 4 lo sometimes, most likely your problem is in the transfer case

 

I told you you would need the shift linkage and bezel if you switched to a 242...
They have a tag on the back with the model number.
YES it matters.
Like I explained before, 87-90 has a 21 spline input, 91+ has 23 spline...
I would try to stay with the 231, I mentioned the 242 swap because I thought it was a DD (I would love FT 4wd in winter).. For a wheeler, you wouldnt use the FT anyway, so theres no point in having it.

 

sorry got a little confused. just didnt mechanically make sense. lol. is 200 a good price for a np 231? i offered him less but thats what hes asking. said its in perfect working order. any way to check that? when i got the cover off mine you could fell where the chain had been hitting the sides of the tcase. was about 1/8 inch deep like it was kicking off the gears.

 

Honestly, if the only thing thats wrong with yours is the chain, and you can wait for a while just replace your chain. But, if you cant wait get the 231. Just makes sure its in that year range, or youll be screwed. I guess thats not a bad price, kinda high, but not bad. I dont know how to check a tcase...

 

The only difference I know in 231's is some have 21 spline and some have 23 spline input shafts.
Count yours and make sure what you got before buying another one.