4wd operation Q

Since I dont' have an owners manual, and this is my first XJ, and the repair books don't say, I have a couple of questions about the NP231 Command Trac setup.

The dealer said to engage 4wd hi while moving (anything below about 50mph) and under acceleration. And to disconnect, put it back in 2wd while accelerating (modestly) as well. Is this right? What are the speed or rpm limits to engage 4wd hi, and is the accelerating necessary? What's the best way? How about neutral?

Any things NOT to do while engaging?

I assume 4wd lo is neutral first and 0 mph like all the others...

Thanks.

Dealer is (as usual) wrong.

You can shift into and out of 4WD HIGH range at road speeds up to 50 MPH. Actually, you can shift a bit faster than that, but I believe that's what the book says (might be 55). But you should NOT be accelerating -- you should be at neutral throttle. Not accelerating, not decelerating. NO LOAD on the drive line.

The only real caution is to be "situationally aware." When my XJ was new, I was exploring an unplowed road in Vermont during a snow storm. I have the Trac-Lok differential in the rear, so I was mobile in 2WD ... until I came to a particularly steep hill. Got about 1/3 of the way up and forward motion ceased. Mind you, the rear wheels were spinning and the speedo read 30 MPH, but we weren't progressing. (You can see where this is going, right?)

So I reached down for the 4WD lever and gave 'er a yank ... closely followed by a cacaphony of very unhappy sounding noises from the general vicinity of the transfer case. I realized very quickly that it's much easier (not to mention better) to shift into 4WD when the front wheels (and drive shaft) are traveling at the same speed as their brethren to the aft of the vehicle.

Low range is NOT shift-on-the-fly. For that you should be stopped, or maybe rolling at 1/2 to 1 MPH, in neutral or with clutch disengaged.

I believe it was only in recent years that D-C started putting the "50mph" limit on the shift...then again if you need to shift into 4Hi at that kind of speed then you REALLY need to slow down.

Neutral throttle has always seemed to work best for me; usually while rolling. Tranny in 'N' to go into Lo, and barely moving is also right. Don't use 4Hi on rainy roads (did I already type this to you today?) but only use it where you actually have wheelslip; try to keep all four tires inflated the same as well to reduce 'bind'

Thanks, it works easier that way ;-)

I used to find (with my old Bronco II) that it would help to be in 4wd hi in heavy rain on the highway, especially when going through deep puddles, to prevent hydroplaning. Ford said it was OK then. Is it really bad to do the same on an XJ?