Part time vs full time 4X4

[Hockeygoon]

I've always heard the difference between part time 4X4 and full time 4X4 is that in part time the front and rear axles are mechanically locked at the same speed. Full time 4x4 in the Liberty meant the transfer case acted as a differential between the front and rear axles allowing them to turn at different speeds.

My question is - in full time 4X4 does the transfer case only send power to the easiest turning axle like the open differential in car? Meaning if the traction is bad enough will the differential only send power to the front or rear axle? If not, then how much? Will the transfer case spin the front draft shaft at half the speed of the rear driveshaft?

 

[teeje]

We have an LSD (limited slip diff) meaning whichever wheel has less traction is where the power will be transferred


2002 Jeep Liberty 3.7L with brand new engine
Sent from my iPhone using Tapatalk

 

[tjkj2002]

I've always heard the difference between part time 4X4 and full time 4X4 is that in part time the front and rear axles are mechanically locked at the same speed. Full time 4x4 in the Liberty meant the transfer case acted as a differential between the front and rear axles allowing them to turn at different speeds.

My question is - in full time 4X4 does the transfer case only send power to the easiest turning axle like the open differential in car? Meaning if the traction is bad enough will the differential only send power to the front or rear axle? If not, then how much? Will the transfer case spin the front draft shaft at half the speed of the rear driveshaft?

Correct with the select trac in full time mode the diff with the least amount of traction will get up to 100% of the engine torque just like a open diff.


When traction is equal,like dry pavement,the torque split is usually about 52% front and 48% rear since the front end naturally sill spin faster due to the slight gear ratio difference between the 2 diffs.

 

[tjkj2002]

We have an LSD (limited slip diff) meaning whichever wheel has less traction is where the power will be transferred


2002 Jeep Liberty 3.7L with brand new engine
Sent from my iPhone using Tapatalk

He's talking about the t-case not rear diff and by the way the OE LSD was only a option on '02-'05 model years.

 

[teeje]

He's talking about the t-case not rear diff and by the way the OE LSD was only a option on '02-'05 model years.

Oh okay I misread that. Thank you. Didn't state which year he had


2002 Jeep Liberty 3.7L with brand new engine
Sent from my iPhone using Tapatalk

 

[Hockeygoon]

Correct with the select trac in full time mode the diff with the least amount of traction will get up to 100% of the engine torque just like a open diff.


When traction is equal,like dry pavement,the torque split is usually about 52% front and 48% rear since the front end naturally sill spin faster due to the slight gear ratio difference between the 2 diffs.

So basically all you need is one tire to have no traction and the Liberty is immobile when its in full time 4X4?

 

[ltd02]

So basically all you need is one tire to have no traction and the Liberty is immobile when its in full time 4X4?

Not sure if it should be that way but I've experienced it. Then it was time for part time and no problem. :shrug:

 

[JeepJeepster]

So basically all you need is one tire to have no traction and the Liberty is immobile when its in full time 4X4?

Correct. Full time is really only useful on partially snow covered roads, or when you think you just need some added traction. Since its splitting the torque between 4 tires instead of just 2, it will actually be somewhat useful. Just the other day it snowed around ~1". They had plowed the roads but there were still areas of snow and ice. Part time wouldve been binding up, but full time was perfect.

Anytime its completely covered or your offroad, etc, part time will be a better choice.

 

[turblediesel]

I use full time any time it's slick out since the back end steps out so easily in 2wd even with the LSD in the back. I only use part-time when I'm on ice, nearly stuck, or helping someone get unstuck. Driving along in part-time seems like a lot of unnecessary wear and tear on the driveline.

 

[JeepJeepster]

The fact that you have an LSD is the reason the rear end steps out so easily. When I had a locker it was scary at times. With the open diff it hardly ever gets sideways unless I set it up perfectly to try to get sideways.

 

[TwoBobsKJ]

The fact that you have an LSD is the reason the rear end steps out so easily. When I had a locker it was scary at times. With the open diff it hardly ever gets sideways unless I set it up perfectly to try to get sideways.

So you got rid of your Powertrax locker?