1. 1052558

    O.K... I understand (kind of) some of the differences between the NP231 TC and the NP242 TC, but not all of 'em. If you're not doing any real off road drivin' but you spend a good bit of time in the snowy midwest, is the command trac alright, or is the selec trac the only way to go? I've never had any problems with the part time 4WD, but I keep reading how there's no comparison. What are the pros and cons, or any interesting info on either.

    edited by: dingus, Jan 29, 2003 - 06:34 PM[addsig]

  2. 1052564

    Just an opinion. The Selec-trac seems to be a work in process, it´s had a few redesigns in the last (18-20 years?). The 231 seems to be pretty much unchanged. The only reasons, I can think of, for a manufacturer to redesign something, is to make it cheaper or better. The 242 has quite a few less parts than the older, 229 or 228. The 229 has had some reliability questions. The last, really reliable, full time transfer I can remember, was the old 203 (which wieghed 165 lbs. dry) and guzzeled gas (but personnally I never managed to break one, though there have been stories).
    In summery (242), it sure is nice to drive from dry (clear) pavement to snow covered pavement, without having to shift in and out of 4X (to save the drivetrain, the tires and being able to turn sharply). But you always have to ask, how long till the next rebuild if I use this thing a little to much.
    Of course, you can ask yourself the same question, if you drive the 231 a little to much on dry pavement. And it is a pain, to shift in and out often, especially when you have to slow way down, to do it.

    edited by: MudderChuck, Jan 29, 2003 - 01:57 AM[addsig]

  3. #3


    and i think the difference between part time and full time is:

    part time locks the transfer case - each axle's driveshafts spins at the same time - this causes the front end to hop or jump around when taking sharp turns

    full time keeps it open - better for street driving when its snowy or slippery, but it won't perform as well offroading in more serious situations...

    edited by: dingus, Jan 29, 2003 - 06:34 PM[addsig]

  4. 1053225

    Speaking of changing "at speed" into 4WD... I am a recent and quite happy owner of a 95 XJ with the part time T-Case. I do not have an owners manual for my Jeep. I know that going into four low at anything other than a stop and transmission in Neutral is a recipe for disaster, or at least the impetus for a transmission/T-case rebuild. What I need to know is, does anyone know the max speeds for changing from 2WD to 4WD Hi and back?

    Thanks for the help. [addsig]

  5. #5


    My owners manual says "To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed." I have the Part-Time NP231 T-case and haven't had any problems shifting between 2H-4H while going 55-60mph. The only thing I've found is it's best to take your foot off the accelerator while shifting, because the engine vacuum is weaker while accelerating (You need high vacuum for a smooth shift).
    Also the owners manual says not to shift into 4L at any speed over 2 mph.

    1988 Jeep Cherokee w/ 410,000+ miles. Now a 100% Electric Vehicle!
    NO Gas, NO Emissions, NO Problem! -- http://www.DriveEV.com/

  6. #6
    Join Date
    Nov 2002
    arkansas, or 34*06'N-93*04'W


    while i have a dana 300t-case and not a np231 i never shift in to 4hi with out being at a compelt stop[addsig]
    82 CJ5 that dont run.... and is no more.... 94 Z71

    J, you wont be forgotten

  7. #7


    I´ve shifted at 30-40 mph with no problems. Sometimes I have to slow down to 15-20 before it engauges and the light comes on. A couple of times when I shifted into 4H it sounded like a mixmaster full of nuts and bolts (usually in the cold). Now I usually shift between 15-20 and leave my hand on the lever to back it out quick if necessary. ;-)

    NOTE: Delayed shifts into or out of 4-wheel drive may be experienced due to uneven tire wear, low tire pressure, excessive vehicle loading or cold temperatures.

    WARNING: Do not drive the vehicle unless the transfer case is fully engauged. Failure to completely engauge a position can cause transfer case damage or loss of power and vehicle control.

    To engauge, shift traansfer case lever from 2WD to Hi Lock while the vehicle is moving at any legal speed.

    Or in other words you give that thing a pull, and you take your chances.

    edited by: MudderChuck, Feb 02, 2003 - 12:05 AM[addsig]

  8. #8
    Join Date
    Oct 2002
    East Tennessee


    Call me a chicken (yea I know your a chicken hehe) but I still stop and shift into 4 hi or 4 low and back again. You can pet a dog you don't know but why take the chance. I just hate to work on stuff if I dont have to. So better safe than sorry. Tug[addsig]

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