Originally Posted by WoodiE55
The Jeep is a 2000-2001 Grand Cherokee, the owners manual is missing but the center console has the following setup:
4WD Part Time
4WD Full Time
What 4x4 system is this?
Also, is 4WD Part Time safe to drive on the road - wet or dry or should it only be used off road?
edit: Nice and quick reply, charlesshoults. lol I was off in Google land pulling down all this for him.
It looks like its a Selec-Trac, possibly with the NP242 transfer case.... You can find the gearing on the differential bolt tabs. In 4WD Full Time mode you can drive it any time on any surface like all-wheel drive...rain, sleet, mud, etc. For 4WD Part Time mode you'll find that when selected, there is an indicator light that comes on on the dash. This is because this mode is important and that indicator light should be considered as a WARNING....in that, Part Time should only be used for that - part of the time, those times when you are only on a slippery surface such as off-roading in mud, snow, etc. The TC locks front and back as one and the wheels will hop or lock up if on the highway. Being on a slippery surface allows driveline stresses to relieve themselves as is needed.
Selec-Trac, look it up:
1) Jeep four wheel drive systems - Wikipedia, the free encyclopedia
Though you'll read that the Selec-Trac was discontinued in favor of the Quadra-Drive II, the NV242 transfer case offers more gear modes and is the preferred. The Quadra-Drive II WJ's came equipped with axles having vari-lok differentials, a type of locker activated by the buildup of pressure from a spinning tire. I upgraded my axles to this and find them to be...not worth the money, and would put Aussie's in if I had to do it all over again.
2) Jeep - 4x4 Basics - 4x4 Systems by Vehicle - 4WD SUVs
Not a bad read, and helps explain a lot.
3) Jeep Select Trac NP 242 Transfer Case Information
Great article. Poke around for more info...
Hope that helps!