Locker/LS with NP242

Hey everyone! I'm looking for firsthand experience with those who have the 242 transfer case and some kind of traction device(s) in their diffs.

Here's some background:
Ride- 88 XJ waggy w/homemade 4" lift on 31 ATs, 4.0 w/AW4, 8.8 3.73 w/ford limited slip rear, open front HP D30 w/3.55.
Driving style- will see more pavement than dirt, interested in mild-mod trails, but I'm not looking to impress anyone... live in NC in the triangle so it does snow infrequently, with some ice in the winter (this season was definitely not the norm) i.e. will want to use Full-time 4x4.

I have a pretty good mechanical aptitude, replaced and rebuilt motors but have never done gear work. Obviously, that is something I now will need to address, either myself or a shop. I have acquired a set of good 4.10s for the D30 and ultimately my plan is to run 33s w/cut fenders which i think will be a fair compromise. Limited budget, looking to make informed decisions...

Here are my concerns:
1) are 4.10s reasonable for above setup?
2) I've searched and read a lot about NOT using an auto locker in front w/242 but most of those threads/comments were anecdotal. I would REALLY appreciate hearing from people who have used the combo or have some form of DIRECT experience. It seems the problems are steering related in full-time 4x4 locked up front...
3) In an ideal world I would have selectables front/rear but that is more than what my XJ is worth and will never pass the budgetary committee. A selectable in front would be next and then a LS if full-time is used (allegedly) and a locker if i want to get hurt/die. Recommendations? Definitely prefer experiential evidence!
4) Rear- already have LS, what are opinions of those who have 8.8 LS's? I've read everything between useless to ideal w/front locker. Again, most of it anecdotally. Anyone out there ACTUALLY used or uses LS rear with or w/out locked front? Street/off-road capabilities

Apologies in advance if these should be in separate threads and I promised I searched extensively before posting.

I feel like my LSD causes more problems on ice than my open diff, maybe my memory is shot. With selectable lockers it's all or nothing, my preference. LSD belongs on your tongue not in your rear end. 4.10s and 31's should be great.

Keep in mind my 01 XJ has a 231 and open diffs And my 97 XJ has 242 and lsd.

I have a Detroit locker in the back/Detroit truetrac up front. NP242/auto transmission with 31 inch general grabber at2 tires. The combo works great with no problem winter driving as long as you don't drive like a teenager. The front trutrac pulls me out of any tail wiggle. I was actually surprised to find a little acceleration actually is best to recover control during those times I purposely cornered fast enough to lose traction when experimenting with this combo's handling characteristics. I see mostly moderate scenic wheeling in my future so I sort of wish I had gone truetrac front and rear. I understand the truetrac is very good in slick off-camber situations where a locker might tend to make a rig slide to the downhill side of the road. I don't have any experience with a locked front in full time 4wd but from what I gather it is far from ideal.

My '00 has a 242 and a trak loc in the rear. It's my daily driver. I haven't had any problems out of it(other than it needs to be rebuilt). Actually, it works a lot better than regular 4wd on the ice we've been getting down here. I've had it in the full time 4x4 position for a week or so for that reason. Sleet coming down now and the roads are supposed to be icy again in the morning.

I don't think I'd put a limited slip in the front D30 with a 242. Definitely wouldn't put a non selectable locker in front with a 242.

If it needs to be rebuilt, does it act like a LSD or open diff?

With my 01 XJ, I usually run 2wd on the highway and put it in 4wd part time on the city streets where I'm more likely to hit patches of ice. With the 97 XJ, I can use the 4wd full time. But sometimes the LSD catches patches of ice under bridges, etc. and it bangs and pulls the Jeep. I just don't remember that with my 01 XJ that does not have LSD.

With selectable lockers, I'd leave them off unless I was off road or trying to back through a bank the plow made. My stock 01 XJ has only gotten stuck once, when I deliberately drove it into a mud hole on my land to see if it would get stuck. I've driven many miles on it in 2wd on crunchy unplowed interstates and made it just fine.

I lived many years in the Southeast with the Jeep so I am familiar with the ice and freezing rain in that part of the country. I felt open diffs and the NP231 were adequate.

Either a limited slip up front or a selectable. like you thought, an auto locker will be miserable on road in full time, in mo opinion making it useless.

not that i know anything about anything, but i disagree.

i'd do it in a heartbeat.

For Minnesota winter driving my ideal rig would be Limited Slip or Selectable Locker in front, and locker in the rear. I use 4x4 in the 1998 (open/open diffs) anytime there is snowy/icy highways and freeways. The 98 will getting a rear locker in the spring.

Currently my 2000 has front and rear lunchbox lockers, and the front locker doesn't like icy roads in 2wd. It will sometime only partially disengage when one front tire is on ice, and the other is on pavement. It may only need some new springs. In 4wd everything is fine.

Lockers in the rear on snowy/icy roads perform and behave exactly the same as the Limited Slip they replaced. Some Limited Slip axles will accept a lunchbox type locker.

If you are locked front/rear with a 242, it is recommended that you not use Full-Time.

md21722 said:

If it needs to be rebuilt, does it act like a LSD or open diff?

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The rear end needs to be rebuilt. Cover gasket was leaking and I didn't notice until way too late. Now it howls. The LSD still works as it should, but chatters once in a while when turning. I've got another rear end to swap in, just haven't gotten to it.

I would not go any lower than 4:56 for 33's.

I'm running Aussies in front and rear did really good in 7in of snow a week ago and today we had about a inch or so of sleet that froze solid on the roads and it did fine in 2wd and 4wd. I was a little worried about it since we rarely get that kind of snow but I was very happy with the way it performed.

MD- how did your LS perform off road?

RK- what gears are you running? Do you find your locker setup adequate off-road?

Machinist- why wouldn't you put LS in front w/242?

90XJ- have you had a locker in front or driven one w/full-time 4wd?

Cal- why would you use one?

Tim- I've read that in 2wd, front lockers are "invisible"... not true in snow/ice?? Good to know they act the same as LS in snow. I know it's not recommended to use a front locker in FT 4wd, but have you ever done it?

Kippo- I've read a little more and it seems to support your thoughts on gears... i may have to rethink this whole thing anyway... do you have 231 or 242?

I'm still very interested in hearing from someone who has ACTUALLY used a front locker in FT 4wd. Also, any LS rear and locked front experience? On and off-road?

Thanks for all the responses so far, much appreciated!

crmerrill said:

Cal- why would you use one?

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Its more the inverse, I would have no hesitation at all about using one. Limited slips and lockers just don't have the detrimental performance characteristics some people fear they do.


Yes, you have to adjust your driving style a small amount with an auto-locker (detroit, grizzly, etc) but not by much - just don't punch it in the middle of a turn. Beyond that, you hardly know they are there and quickly forget about them.

I have no problems or hesitations about using lockers, but there seemed to be a general consensus to not have one in the front while using full-time 4wd. I don't want to stop being able to use FT and I have yet to read/hear from someone who has actually done it and shared their tale.

Although, maybe that's my answer...

I would agree there, although that wasn't part of your original question.

If you don't wheel a lot of big rocks, you could put an Ected up front.

Its a limited slip when unlocked, and locked when locked. Them have been known to unlock under extreme load when they get old, but for 95% of people that never happens. Depends on how you use your rig.

My gear ratio is 4.56

I would not put an auto-locker in the front with 242 in Full-Time. The open diff in the FT position means torque will transfer to the front on its own, no driver intervention required. Do you need to stab yourself in the eye to know its going to hurt?

Selectable locker is something different. Limited slip with clutch pack is something different, in another way.

I have a 8.8 with a factory lsd and it works well I've figured out when I'm not really gaining like I'd like to I tap the brakes and it locks the rear up tight. I get all squirrely in the show and ice but I drive with a heavy foot most of the time. I don't have a 242.

cal said:

I would agree there, although that wasn't part of your original question.

If you don't wheel a lot of big rocks, you could put an Ected up front.

Its a limited slip when unlocked, and locked when locked. Them have been known to unlock under extreme load when they get old, but for 95% of people that never happens. Depends on how you use your rig.

Click to expand...

Yeah, my apologies if I wasn't very clear. That was supposed to be my question #2.

I have not read positive things about the ected, but most of those posts are from 2009-2011, so I'm not sure if anything has changed since. I've been thinking about an eaton e-locker or an ox, but $800-1000 is quite a chunk for my heap. I HAVE to change gears just to get it back on the road and was hoping to toss in a locker to kill a couple birds with my poor stone...

As far as how I use it... a bit of everything. I'm not huge into hardcore crawling, don't care for mud, but my pride doesn't like getting tugged/recovered either.