Rumple

Just bought my first Jeep - 1999 Cherokee Classic, 242 transfer case, straight 6, 4WD drive train. I have done some research on this so I will pose this more as true false to see if I read right. I will likely be spending my time in either 2WD or Full time 4x4 (whichever can be used in any surface - both are in green text on transfer case). To that end:

True or False: If I want to shift from 2WD to full time 4WD, in theory this can be done on the fly while driving at relatively high speeds. However, I likely would not have a need for that, so it would be fine for me to, while stopped, put the jeep in neutral, foot on brake, then shift down from 2WD to Full Time 4WD, put jeep in Drive once shifted and go.

Is the above the recommended or optimal solution and best in terms of wear and tear on The Jeep, true or false? As I also read for the other options (4wd part time, lo), for those you want to be moving slowly around 2mph or so, then do the above - buy again, I don't think I'll be using those so I just wanted to confirm the best approach for the above as this is my first car with 4WD.

Thanks.

Gee oh Dee

You read correctly, and the info is true.

Anything up to roughly 50 mph or so is safe to shift on the fly. I believe the best way to put it is "any reasonable speed" should be safe.

As for shifting into 4low, yes, its best to be moving slowly.

I never believed it until i saw it in the owners manual. And then I actually tried it on my rig, and it shifted into low better/easier than when I was not moving.

Seems they are designed to function this way.

Rumple

Ok thanks - but does the Jeep need to also be put in Neutral when shifting? The put back to drive after complete?

Gee oh Dee

No, not when going into 4hi.

4 low you should be moving at 1-2 mph, and as you move from 4hi to 4low the tcase passes its own neutral.

The transmission and tcase both have neutrals.

Cane

Is there any harm to be stopped, in neutral and then shifting in 4hi/lo? it's what I always do

Gee oh Dee

Maybe wears the syncros a bit.

PocketsEmpty

Really? I've always done 4 lo at a dead stop in Neutral first. Seems to be the safest way..

Gee oh Dee

Read the owners manual.

I didn't believe it either, til I read it with my own eyes.

thatXJguy

Four wheel drive Full Time can be shifted into at any legal speed whatsoever. I've had it up to 80, my buddy has a liberty and has had it up to 100... same full time option.

Part Time I don't recommend using on the road at all.

You can shift on the fly, or you can shift in neutral. It's your choice!

Gee oh Dee

Why you need 4wd at 80-100mph is beyond me.

thatXJguy

You don't. The option is just there. In some cases traffic goes a little faster than 50mph. If you want to go 50mph in four-wheel drive full time, you might as well keep up with traffic in four-wheel drive full time.

There is no boundary at 50mph; I think this is more of a personal limitation than anything. The owner's manual also says, "any legal speed."

On numerous occasions I use full time to prevent unwanted burnouts in the rain when beginning to accelerate from a red light turning green. Most of the time this includes highway driving and it's never a bad idea to use four wheel drive full time for the additional traction it offers... even at those slightly higher speeds.

Gee oh Dee

I have yet to see any 100mph speed limit signs.

I've driven in snow at 75+mph in 4wd. It was incredibly stupid, and i was traveling well below 75mph when I shifted into 4wd. But I did it.

And looking back, I can reiterate it was stupid. Any condition requiring 4wd of a Jeep Cherokee is hardly a time for it to be traveling at triple digit speeds.

thatXJguy

I've gone anywhere from 0-80mph in Full Time. There are plenty of 70 mph speed limit signs on freeways here.

apac020

I think his point was: if the conditions mandate the use of 4WD, it's probably very dangerous to be going that speed in the first place. Whether it be in wet, snowy, muddy, our any other slick condition. If the conditions aren't slick, then you wouldn't need 4WD.

So under what conditions would you need 4WD going 70+ mph?

Morat

Going back to the original question, you got it right
Just don't use 4PT on surfaces where you have good traction especially on corners or you'll hear a nasty clunking from the transfer case when the chain skips. You can do a few yards forward and back in straight line for testing if you like, but that's all I'd do.