2WD, 4WD, Part Time 4WD?

[Shells_k]

Okay, I have never driven 4WD before getting my JGC. It really came in handy driving home in a bad snowstorm last night. I dont really understand the whole 4WD thing though, especially when looking at the Shifter. I have 2WD (which I have kept it in until yesterdays big storm), Part-Time 4WD, Full-Time 4WD, and Low. Can someone explain the differences to me, and when it is appropriate to use them?

Also - A buddy at work said to makes sure I dont keep it in 4WD all the time, because if I use it on dry pavement I will ruin the Jeep?

[95zj-tilshedies]

Your transmission case (TC) is the 242:
2WD = two back wheels turn (drive in this mode most of the time to get the best gas mileage)

Part-Time 4WD = all four wheels turn all the time (use this on wet or loose roads ONLY [you can only use this PART-TIME] -- because all four wheels are locked (they are all getting power, the road must be wet or loose [dirt, gravel, snow, etc] to allow for the front wheels to continue to have power --- your friend was right: don't leave the TC in this mode or you can damage it)

Full-Time 4WD = you can leave the TC in this mode all the time if you wanted to (thus, FULL-TIME). While still 4WD, the front wheels are controlled by a limited slip differential in this mode, making it safe to use on all road surfaces.

LOW = or 4LO -- this is also 4WD, but you should really only be using this in pretty extreme circumstances, and the Jeep should not be driven more than about 5 MPH in this setting (also only on loose or wet roads).

BTW, this may be printed on the back of your driver's side sun visor.

Hope that this helps.

[fredjacksonsan]

While the last post is basically correct, just wanted to make these 2 points:

In any Part Time mode, either 4hi or 4lo, the center differential in the transfer case is locked, and the front and rear axles turn at the same rate. These modes should NOT be used on dry pavement. The owner's manual says that 4LO should be used at less than 25mph. If you want to go faster, keep an eye on the tach and remember that you should only shift into or out of 4LO at 3-5 mph or you'll damage the transfer case.

In Full Time, the center differential allows the front and rear to turn at different speeds, so as 95zj said it can be used all the time if you like.

Most GCs don't have a front limited slip differential.

[Shells_k]

Thanks so much for the info guys, I sure appreciate it!