Hi I'm sure this questions has been asked before but i haven't come across a clear answer

When exactly can i safely switch into 4hi in my 1993 4.0 Auto Cherokee Sport?
I've seen some people say you have to come to a full stop like you do with 4lo and others saying you can switch on the fly at any speed you want as long as you aren't giving it gas so which is it?
Also when you're in 4hi is there a limit to how long you can keep it engaged? Should I use it very sparingly and reserve it for extreme weather conditions? (I live in canada so I mostly need it for the large amounts of snow we receive)

Anyone who can help give me a rundown would be appreciated, thanks!

 

Shifting on the fly is fine. The biggest thing is to make sure you're not driving it on grippy dry pavement in 4WD.

 

would that be okay at highway speed? And how long can i keep it engaged?

 

Does your transfer case shifter have this pattern?

2H
4H
N
4L

 

Yes it does

 

Here's how the factory suggests you shift the transfer case, and it works well for me. Quoted from the owner's manual.

"To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed".
4L position: " To engage, slow the vehicle to 2-3 MPH , shift the transmission to Neutral, then shift the transfer lever to the right and pull firmly rearward to 4L". My addition- (Reverse this procedure to shift from 4L).

It is fine to use 4H at highway speed. Make sure you only use 4H or 4L in loose, slippery conditions (snow, mud, gravel, etc). A road that is simply wet IS NOT considered loose, slippery conditions, and 4WD SHOULD NOT be used.

It is okay to use 4WD as much as you want/need. You should engage it once per month or so, just to keep everything exercised and lubricated.

 

You can engage at speed for 4hi if you need to, but just make sure when you engage it, that you are not on the gas, just coasting. I personally do it at a stop light or before I start driving. When I disengage, I usually shift into reverse and back up, maybe just 10 feet, to make sure it disengages. I know you don't have to, but it's how I was taught.

Remember, 4wd is to get you out of trouble, not into it. (Been there, done that).

 

Do you happen to still have a manual in the Jeep?

4HI any legal speed. It may be necessary to release the accelerator after the shift to expedite the shift.

4H is synchronized and there's no locking hubs to deal with so as long as you aren't spinning the back tire and going relatively straight when you shift you'll be good.

4L slow to 2-3 MPH shift to N on the trans then pull back to 4L. Engage Drive and continue on.