alvee42

I just purchased my first Jeep. A Cherokee with four wheel drive. It is a 1999. I have never owned a four wheel drive car. My question for anyone that could help is:
When do i use "four wheel part time" vs "four wheel fulltime". I do understand when to use four wheel low, but am confused as to when i use either of the other two.
Thank you for your input
Al

crug75hid

Well, it's great. Normally all the vehicles will run with two wheel drives, but for the special road conditions the companies have developed four wheel drive vehicles exclusively used for hill/slope/desert/muddy areas as the torque will be distributed to all the wheels and the vehicle can be easily run on the above mentioned areas. so for the common flat surface roads it is preferred only two wheel drive for odd road can be opt for the four wheel drive.

alvee42

Can you tell me when i should use the fourwheel part time vs fourwheel fulltime?
thanks
Al

xjod

Full time will work on any surface. It's great on slick roads. Part time 4hi or 4lo is only used off road.

alvee42

Thanks that info really helps me understand

Stan6406

Actually Full time should only be used off road/adverse road conditions I've never had to use fulltime 4WD low on the street. Part time is good for general driving with slick roads

alvee42

Well, now it seems that sjod and stan 6406 have conflicting info, so now i'm back to being confused. Can anyone clear this up?
Thanks
Al

Mike H.

Full time mode utilizes an internal differential to allow the vehicle to drive on road without suffering bind. It splits tq 48/52 front rear.
Full time works great on in situations where the road varries from high traction to low traction. Example would be a road that has snow patches and bare patches, a maintained gravel road... some use it in the rain...
Full time"could" be run on dry pavement but there is no need to do so.

Part time hi mode bypasses the internal differential and locks the front/rear to a 50/50 tq split. in this mode, on a high traction surface (paved roads) the drivetrain will bind up when turning. Rather hard on the transfer case.
Part time hi sould only be used on gravel roads, or completely snowed over roads.
Personally, if I had the 242, I would never use the part time hi setting.
I've owned vehicles with the 249 and 247 (both having full time 4 hi operation) and I simply cannot imagine a situation that would warrent locking the front/rear drive shafts together in hi range.

Part time lo is pretty obvious, (and locks the front/rear driveshafts together) and you said you understand that...

take care.

alvee42

Thanks Mike for your explanation. I think i understand how to use it now.
Al

nasonguy

Mike H hit it on the head, I think stan just got his terms mixed up.

Full Time = You can drive the FULL TIME with it on, meaning you can use it all of the time, no matter what surface you are on, without damaging any components of the drive line.

Part Time = You can ONLY drive with it PART of the TIME, meaning only slick surfaces, like Mike said, on gravel roads or fully iced over or deeply snowed in road. Like was said before, using this on dry pavement (or any high traction surface...) WILL damage the drive line due to binding...

Stan6406

if I put mine in full time 4wd it binds up. Part time it doesnt

4.3L XJ

Stan, I think you have a different transfer case than alvee. I am guessing you have the NP231 while he has an NP 242 or 249.

xjod

So Stan since your profile states that you have a 231 and my XJ has a 242 I'm speaking from experience. FULL TIME as read on the dash and transfer case shift lever can be used at anytime, though pointless unless road conditions warrant it's use.

Stan6406

The 96 I have has the 242
the 87 I have has the 231