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Unread 02-20-2012, 09:25 AM   #16
LouC
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If you live anywhere it snows often in the winter, the 242 is what you want, much more versatile than a 231, that full time feature adds a lot of safety. I have it in my 98 ZJ which I've owned since new and it has been great in 14 years worth of northeast winters. You can put it in full time at the start of winter and leave it there till spring if you want to. I did that many of the years and as long as you keep oil in it, maintain the tire pressure, and keep all tires the same size you are unlikely to have problems with it. Great for towing as well, I towed a 4000 lb boat up steep hills on dry roads were you would have had wheelspin with an open rear diff in 2 wd and no problems at all, no problems on a steep sandy boat ramp either. In fact I have only used 4x4 part time on my ZJ, maybe 3 times in all the years I have it, and that was after record breaking blizzards here in NY. Off road and no snow, sure the 231 is fine, but for all weather on road traction you can't beat a 242. That is why I chose the JEEP, over the Ford Explorer and Chevy Blazer (crap electronic 4x4 maybe, LOL) and the Nissan Pathfinder and Toy 4 Runner (part time only back in 98)......

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Unread 02-20-2012, 08:18 PM   #17
WJWKXJZJ
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Quote:
Originally Posted by LouC View Post
Great for towing as well, I towed a 4000 lb boat up steep hills on dry roads were you would have had wheelspin with an open rear diff in 2 wd

I was advised against this by my Jeep owner's manual and some others.

Were there any adverse side effects? D30 taking 48% of the torque is supposed to be bad.... ?
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Unread 02-20-2012, 08:27 PM   #18
PhilipJ
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It's true that the 231 is a little 'stronger', but it shares the same exact weak spot as the 242 -- the smaller diameter part of the main shaft by the tail cone. It's extremely unlikely that you'll break anything else in a 242 that you wouldn't break in a 231 under the same conditions and driving habits.

The biggest thing the 231 has going for it is the loads of aftermarket parts and options because it was put into so many other vehicles, plus you can drop a 4:1 into it (even though an Atlas is only a few hundred $ more at that point.)
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Unread 02-20-2012, 09:10 PM   #19
Sycoglitch
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There's was some long posts so I didn't read every little detail here, preferably cause the details of the 231 etc. but it's simple if you live where there's 5 months of constant snow then the 242 might be for you but the 231 is great off road and the on the fly helps for those 3 months of snow. I shift constantly on my 231 between snow, dry, ice , dry, heavy down pours, dry etc with no problem for years now and she's never let me down. That marginally stronger 231 can help you outta mid and up rocks if you aint got wicked winters.
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Unread 02-21-2012, 01:05 AM   #20
sAe23
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Silly question:
With "Full time 4WD" having an "open diff" in the transfer case, and IF you have open diff's in each axle, under low traction conditions, could you end up with
ONE wheel drive??
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Unread 02-21-2012, 05:58 AM   #21
JrMechanic
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Originally Posted by sAe23 View Post
Silly question:
With "Full time 4WD" having an "open diff" in the transfer case, and IF you have open diff's in each axle, under low traction conditions, could you end up with
ONE wheel drive??
Yes, which is why the primitive full time feature of the 242 is worthless when compared to a true full time case such as a 249 or 247 which are capable of differentiating torque between axles.
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Unread 02-21-2012, 07:58 AM   #22
1990JEEPXJ
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Quote:
Originally Posted by JrMechanic

Yes, which is why the primitive full time feature of the 242 is worthless when compared to a true full time case such as a 249 or 247 which are capable of differentiating torque between axles.
Except that the 249 has a viscous coupling which is known to go bad. Then your screwed because there is no 2wd setting in the 249. I'll stick with my 'primitive' 242 which will be much more reliable. I, nor anyone else that I know of, thinks full time is worthless. Yeah if you're running some hardcore trails it is. But for its intended use, it's perfect.
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Yea, and I thought it was one of the 11 Commandments:
11) Thou shalt love, cherish, and honor till death, thine square headlights above all other earthy things sayith the Lord.
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Unread 02-21-2012, 09:43 PM   #23
LouC
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to answer some questions...
1 You CAN leave a 242 in full time all the time, but it minimizes wear on the chain, if you don't
2 Yes because the center diff in a 242 is open in full time, you can wind up with one wheel drive, with open rear and front diffs BUT in practice, I drove through several years of very bad winters in NY, almost always in full time, front and rear diffs open, and was never close to being stuck. If you had your rear wheels on glare ice, and fronts on snow, or dry pavement, you could spin the rears, but if you ran into those conditions a lot, just shift to part time. Problem solved.
Personally, I'd still rather have a 242 than a 249, or even 245, because they are simpler, less to go wrong. I think the Jeep auto engaging full time cases are better than most others, but you can have issues with them. I have a 245 on my Hemi WK, it works GREAT, but with electronic control, there is more to go wrong.

And for snow driving, I used snow tires, not for forward traction, but to have the safest stopping and turning traction. With good snow tires, my ZJ never got stuck, ever, in full time. I shifted it into full time in Dec and left it there till March, every winter, no issues with the t-case.
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Unread 02-22-2012, 11:52 AM   #24
DezertXj88
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I've actually been thinking of swapping in a Np242. Currently I have a 21spline Np231, works great and all..And then I have a matching 21spline np242 in my parts jeep.
I don't/won't need a SYE since I'm at 3" and not going higher. Wondering I if I should do it..
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Unread 02-22-2012, 01:23 PM   #25
1990JEEPXJ
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Quote:
Originally Posted by DezertXj88
I've actually been thinking of swapping in a Np242. Currently I have a 21spline Np231, works great and all..And then I have a matching 21spline np242 in my parts jeep.
I don't/won't need a SYE since I'm at 3" and not going higher. Wondering I if I should do it..
Since you arent looking at upgrading the case with an SYE and what not I would totally do it. I love my 242.
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Originally Posted by Joe Dillard View Post
Yea, and I thought it was one of the 11 Commandments:
11) Thou shalt love, cherish, and honor till death, thine square headlights above all other earthy things sayith the Lord.
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Unread 02-22-2012, 01:34 PM   #26
DezertXj88
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Ya I'm thinking about it more and more..Gotta pull out the 242 and check it out..when pulling it apart is there anything to look for?
Also hows the locker situation with the 242..obviously I can't lunch box locker the front and still expect to drive in 4wd..but what about the rear? Can I toss a spartan in the rear and now worry about anything binding up with the tcase?
I know about lockers and stuff. Just need to know how they work with a 242 I guess.
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Unread 02-22-2012, 02:26 PM   #27
Timo_90xj
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249s downsides are the viscous coupling and the lack of 2wd/ 4 part time high. The VC usually lasts around 100k-150k, which isn't bad but sure could hold up a little longer.

Then again, having owned two XJs with the 242, and the ZJ that has the 249 I can tell you the 249 beats the 242s full-time option on snowy roads 100-0. There honestly is NO comparison between the two. The primitive full-time option on the 242 is just that - a very simple and primitive "AWD", which instantly turns into a one- wheel wonder when the road is actually slippery. Try going up a snowy inclide on a slippery city road.. You'll be stuck in no time. Try that with a 249 - no problems. In slippery weather, I got stuck with the 4FT numerous times and had to swap into 4hi to get myself up a hill. This with studded winter tires. Not once have I gotten myself stuck with the 249 driving in non- plowed city roads.


242s 4FT option sure is better than the 231s part time for certain road conditions, but when it gets a little nastier, you're not going anywhere with it. 4 part time hi does get you mocing, but you loose the better handling from an open or LSD center diff. I sure did love 4FT on the XJs, but a true AWD is a whole lot better in providing grip when you actually need it. 242 gives you (close to) equal torque split on dry roads and good grip, but when it's slippery you'll have 100% of the power going where it shoudn't. With a torque- biased 4wd like a torsen, viscous coupling or a gerotor, you will have the torque directed to the tire where there is grip available.

242s 4FT is not worthless, but it's just an overly- simple solution to a problem if you ask me. That being said, I'd rather have a 242 than a 231 - and yes, at times I have missed the different options of the 242 with my ZJ. I initially thought about swapping out the 249 to a 242, but after two years, that isn't happening


..oh.. wait.. we were talking about 231s and 242s 231 is the choise for a Jeep that mostly sees dry/ wet roads and is being wheeled. 231 has superior aftermarket support over the 242 and is slightly stronger and smaller in size. If you DD your XJ and have snowy or icy roads fairly often during winter, 242 is the way to go. It's not a bad TC at all. Limited aftermarket support and slightly less durable than a 231, but not a big problem unless you're running 35s or 37s and beat on the XJ hard. People are running 231s/ or doubler 231s with up to 42" tires. I'm gonna attempt on running 42s with the stock 242 and hack 'n tap SYE Given that I have 7.6 gearing on the axles with portal boxes, I'm not really affraid though..
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Unread 02-22-2012, 02:54 PM   #28
LouC
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I used studded tires on my ZJ, yes the superior Nokian Hakka SUVs, never got stuck on hills, in FT, some hills you could not walk up.
When those wore out, the new Nokian Hakka 5 was uber expensive, now I have a set of General Grabber AT2s studded, still don't get stuck!

I'm thinking maybe it was the combination of a 4.0, 3.55 gears, heavier ZJ body, maybe thats why my ZJ did better in snow. Not so much power to spin the wheels against the open center diff.

You want to try something amazing, try a WK Hemi, with Quadrdrive II, the way it totally tames over 300 hp in the snow is nothing short of amazing....
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Unread 02-23-2012, 01:34 AM   #29
DezertXj88
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Its official for me..I'm swapping a 242 inplace of my 231. I can still run a lunch box locker in the rear and still have full time which is what I want!
I have a ax15, so maybe I'll be the first 5speed/np242 combo..AMC/Chrsyler never offer them both together!
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Unread 02-23-2012, 02:03 AM   #30
1990JEEPXJ
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wont be the first. i guarantee you that. its been done over on NAXJA. id read up on it over there
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Quote:
Originally Posted by Joe Dillard View Post
Yea, and I thought it was one of the 11 Commandments:
11) Thou shalt love, cherish, and honor till death, thine square headlights above all other earthy things sayith the Lord.
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