Can someone explain to me in basic terms the difference in mechanics and what happens when going from Full Time to Part Time?

 

If you are referring to the transfer case then it means this:

Full time puts the transfercase in gear and alallows the front tires o spin at different speeds, meaning it "gives" a little on wet roads, gravel and so on. When it rains and I'm driving city streets ill throw it in full time and I can drive like a mad man and will never get the tires to break loose. Its gets good traction in the rain.



When using part time it slightly locks the transfercase to allow less or no slipping on hard surfaces. It is only used for loose terrain never paved roads or wet roads. It will bind up when turning and damage the gears/transfercase.

 

^^^^^i concur doctor.

 

What about 4 high 4 low?

 

But is it not the diffs that allow turns without binding?. That lever doesn't do anything to the diffs just the transfer box. I still don't get it really.
I used to drive a Land Rover Defender and that has 1 lever for Hi-Lo (its permanent 4wd) and a separate lever for diff lock to get you out of a bad spot. That lever locked the diffs up I think as all wheels turned regardless. My XJ has an LSD for that reason so when you say "slightly locks" what is it actually doing? Sorry "I just gots to know"

 

Well that just changes the ratio to final drive in the transfer case I suppose!

 

4hi keeps the same ratios as if you were in 2hi, so you could technically still run your top speed in 4hi (I would highly discourage it though). 4lo drops the ratio to a much lower range, so it's more like driving a tractor than a road vehicle. It gives you much better stump pulling abilities and better traction because it's less likely to spin the tires etc. Hope that clears it up a little bit!

 

On a np242 transfer case the 4hi ratio is 1:1 in 4 low its 2.71:1 gear ratio.


As for the part time-full Time thing.

Full time lets the front drivshaft spin at different speeds than the rear shaft inside the tranfercase.

Part time locks the front and rear drive shaft at the same speed which would cause the binding.

A locker in the axle is different from the transfer case locking up the front and rear driveshafts.

Does that clear it up a bit?

 

Crystal...many thanks