Your opinion on 242 to 231 swap?

HELP! Your opinion on 242 to 231 swap or rebuild?

Sorry this is so long but it getting complicated. Here is my problem. I've got the 242 in a 90 Limited renix 4.0, AW4. Some time ago the chain started slipping and has got so frequent that any serious pressure on it will make it pop like crazy and it also seems that at a side angle the chain slips off entirely until I let of the gas and it catches again. So it seems to me the chain is very stretched. Will the cogs be toasted to? Well either way I don't know what me best aproach is at this point because if I rebuild it/replace it/swap it. They all cost money it if I going to spend anything I want to be happy with my choice.
Also I plan on a longarm, axle swapage and 35s in the future if that matters. In addition I pulled the following quote off the Rubicon Express site and was wondering if anyone has experienced this or can explain it. "Over 3.5-inches of lift on a full-time NP242 unit may cause unacceptable vibrations on the front driveshaft, when driven in ”part-time” or locked constant use 4WD." I've got the 5.5 LA on my TJ and IMO its one of the nicer, better quality to price kits out there and Would like to put it an my XJ and that is why I mention the vibration blurb.

I am aware of most of the details involved with the swap, I think...?
1. Spline count(what year was the 21/23cut off for the 4.0?I think mine is 21...?)
2. input length(or will either work for an auto?)
3. need 231shifter plate

I am in the air to rebuild or swap. I've heard mix reviews about the 242 so I'm not sure what to do. I have a TJ and the 231 works flawless. It does NOT pop, shifts easy and smooth so that why I'm thinking about the swap. The drawback is I may get one from a jy I don't know the history or will this one have a half stretched chain? and it may cost more than me rebuilding.

How much am I looking at either way?
If my tranny is in fact 21 spline and I only can get a 23 case than I do have a 21 input gear available form a buddy that did a Vortec 5.3+ whatever tranny comes on that swap on his 4cyl YJ and used the AA kit to connect to the x-fer case. (Will that work?) Its not an issue having to pull the new one apart to change the gear because I want to do a SYE at the same time whether I rebuild or swap.

I know the difference is the FULLTIME selection with the diff but that doesn't seem important to me. I live in the desert and wheel rocks and dirt/sand mostly and never see snow unless its a snow run!

Maybe my 242 was just junk from the time I got it but it also never shifted as well as my 231. I had to really force it. Is that normal or is mine just junk?

Sorry for all the ?s but the more a research this the more confused I'm getting on what to do. Any help with my decision would by awesome. And maybe the most straight forward details on the swap.

it's a matter of opinion.

personally i always look at things as.....less parts=less stuff to break.

so i'd go with the 231 over the 242 any day. plus i don't really understand the purpose of "fulltime" 4wd. if you need 4wd, put it in 4wd. if it's dry out, put it in 2wd.....it can't get any simpler.

Less parts, less to break. I would think the diff would be the first thing to break. Exactly my original thought on the whole thing. thnx

Another question. Is there a drive shaft length difference?

I am looking at doing the same thing, and I think I have the 21 spline input shaft, but figure it will be easier to find a newer 231 or I may try to find a 241. if you don't mind splitting the case as it sounds you don't, just use the input shaft from the busted 242 in the new 231 like this guy did:
http://www.hobbyguild.com/jeep/index.html

that way it is the correct length and number of splines

i'd go for the 231 for simplicity. invest $100 and buy a new chain for it too. the link mentioned the shift sequence is backwards now... its likely because he put in a TJ/YJ 231 and they use a different sift lever on the selector shaft that points the lever UP as opposed to the XJ lever pointing it down. and i've been told the input gear and the planetary gearset are a wear-in to become a "matched" set. if you mix/match them you may be inviting failure.. kinda like you dont mix/match used axle ring and pinion sets..

I would go for the 231 also but...

It isn't the chain slipping. It is the springs that hold it into 4wd. They get weak and cause a slippage like that.

scorpio_vette said:

it's a matter of opinion.

personally i always look at things as.....less parts=less stuff to break.

so i'd go with the 231 over the 242 any day. plus i don't really understand the purpose of "fulltime" 4wd. if you need 4wd, put it in 4wd. if it's dry out, put it in 2wd.....it can't get any simpler.

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Or you could just shift into fulltime and never need to shift again.

I'll have to stop over at your place and let you drive my DD 94 XJ with 3" of lift and 33x10.50-15 BFG's on it.

I was out joy riding around in plowed up snow last night and was crawling threw some huge snow piles in fulltime. The snow is still on my hood and packed in my grille. Most of the backroads are covered in packed snow in spots and some roads they don't plow. I would have needed 4wd many times but I never needed to lock the t-case, fulltime was more then enough.

For the original poster a 231 would be a good choice. Get a HD SYE and maybe a wide chain.

TNT said:

Or you could just shift into fulltime and never need to shift again.

I'll have to stop over at your place and let you drive my DD 94 XJ with 3" of lift and 33x10.50-15 BFG's on it.

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I understand how the fulltime works. just don't really think it's worth having all the extra parts that could break. i don't shift my 231 that much. if it's mostly snow out with a few dry patches, i just leave it in 4wd. if it's mostly dry out with a few snow patches, i just leave it in 2wd. if i'm playing around on snowbanks and other stuff, i leave it in 4wd till i'm done playing then put it back in 2wd. since my whole XJ is build on a junkyard budget due to lack of funds and the fun of "building it cheap", i like the less parts theory.

like i said......it's another one of those topics that's a matter of opinion and personal preferance.

and you're more than welcome to stop by anytime and talk jeep.

scorpio_vette said:

I understand how the fulltime works. just don't really think it's worth having all the extra parts that could break. i don't shift my 231 that much. if it's mostly snow out with a few dry patches, i just leave it in 4wd. if it's mostly dry out with a few snow patches, i just leave it in 2wd. if i'm playing around on snowbanks and other stuff, i leave it in 4wd till i'm done playing then put it back in 2wd. since my whole XJ is build on a junkyard budget due to lack of funds and the fun of "building it cheap", i like the less parts theory.

like i said......it's another one of those topics that's a matter of opinion and personal preferance.

and you're more than welcome to stop by anytime and talk jeep.

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I think it depends on the jeep, situation you drive in and a few other factors.

I am a 242 hater for big jeeps but its a great tcase if you drive on sketchy roads. in fact they are better suited for patchy ice then a 231 is. If the jeep is lifted and has big tires though? No way, go with the 231

DrMoab said:

I think it depends on the jeep, situation you drive in and a few other factors.

I am a 242 hater for big jeeps but its a great tcase if you drive on sketchy roads. in fact they are better suited for patchy ice then a 231 is. If the jeep is lifted and has big tires though? No way, go with the 231

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Thats why I'll be upgrading to a wide chain, 6 planetary lowrange gear set, the 32 spline output(with a 241 hack-n-tap), the HD AMG center differental gear set and a few other parts. This will upgrade its torque rating from 1486# to more then a 2000# rating. This is a higher then a 231HD rating.

Thank for all the input. Keep it coming because I'm learn even more about the different options within each case to beef them up. What about a Teralow kit or am I just better get an Atlas at that point? Because I know they're not cheap.

I have a 2000 XJ with a 242 4.0lt AW4 and I dont like the part time 4wd. Sometimes I hear strange noises when I put it in part time so for that reason I dont use part time. However the 242 works great in the snow,mud and sand. If I were to change it down the road I would just get an Atlas.

you could also go with a factory jeep rubicon transfercase with factory 4:1. it be cheaper than an atlas.

I've looked a couple times for a Rubi case but everyone wants a fortune for them.

90XJLtd said:

I've looked a couple times for a Rubi case but everyone wants a fortune for them.

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they also want a fortune for the atlas.

buy a new rubi case and get a warranty.

a brand new rubi case from the dealer will run you somewhere around 1,200-1,400ish last time i called around. and if you have friends that work at dealers, or even small repair shops, they can probably get them cheaper.

you'll also need a new driveshaft to go with it unless there is a way to go from the flange to a yoke (haven't look into it that detailed yet). but overall you get a better deal then if you go with the tera 4:1 kit for almost the same money.

Keep 242 and run high-pinion axles.

Problem solved.

scorpio_vette said:

a brand new rubi case from the dealer will run you somewhere around 1,200-1,400ish last time i called around. and if you have friends that work at dealers, or even small repair shops, they can probably get them cheaper.
you'll also need a new driveshaft to go with it unless there is a way to go from the flange to a yoke (haven't look into it that detailed yet). but overall you get a better deal then if you go with the tera 4:1 kit for almost the same money.

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Where have you seen them that cheap? Because for that price it may be a better idea over building a 231.

I say do it.....