4 part time or 4 full time??

barhpr · **Posted:** Sat Dec 03, 2005 7:40 pm

As this is my 1st winter with the jeep,which to you guys use when?I read the manual and pretty much didnt get a good explaination. Im used to lockin in the hubs..old habits are hard to kill. :roll:

AdamIsAdam · **Posted:** Sat Dec 03, 2005 9:24 pm

If you're driving on the street, use Full Time. Only go to Part Time if you are in very tricky and/or deep stuff or stuck. If you use Part Time on the street, you'll have to be aware that by having the center diff locked, some tires somewhere will have to slip to make a turn. This could envoke a slide on the street during turning in snow. It's easier to get it sideways in part time during street driving.

Play with it. Get the hang of how your KJ reacts to what condition. I generally put it in Full Time whenever it's wet or slippery. Hey, I paid for my $395 transfer case, I'm gonna use it. Part time is for off road or serious snow "playing" around.

Just my experiences

pixeldzn · **Posted:** Sat Dec 03, 2005 10:42 pm

I moved this to 4x4 Discussion so you get more responses. A lot of guys who might know the answer don't look in the Midwest section.

BTW, I can't answer becuase I only have part-time, but I will attest to the fact that my renny breaks lose preety easily during a turn when I an in 4-HI.

Tokyojoe · **Posted:** Sat Dec 03, 2005 11:21 pm

I thought all Reny's have the 4-Part/4-Full.

We had a few inches of snow today in Colorado and I had to use Full time due to the roads still being covered and icy in the morning. It felt really good with my MTR's on compared to the stock SRA's.

AdamIsAdam · **Posted:** Sat Dec 03, 2005 11:36 pm

it was optional on the 2003 MY.

raceinfan · **Posted:** Sat Dec 03, 2005 11:37 pm

we had a great amount of snow last year & all I used was 4hi (part time) & both my KJ's did fine didn't slide once,the only time it's been in 4lo (full time)is when it went on it's madin voyage wheelin this year :?:

Waldn · **Posted:** Sun Dec 04, 2005 2:43 am

raceinfan wrote:

we had a great amount of snow last year & all I used was 4hi (part time) & both my KJ's did fine didn't slide once,the only time it's been in 4lo (full time)is when it went on it's madin voyage wheelin this year :?:

4lo is not full time, Full time is on Select trac models between part time and neutral still hi range 4lo is part time low range

crdawg · **Joined:** Mon Sep 12, 2005 10:55 pm **Posts:** 98

go to the jeep website and it explains when to use the different transfer case selection,also what is parttime and what is fulltime
http://www.jeep.com/liberty/4wd_capability.html

LibertyCRD · **Posted:** Mon Dec 05, 2005 11:44 am

Is the center diff. on these KJs truly an open differential?? If so, then it's possible that even in Full-Time mode you could get into a situation where only one tire is spinning, right?

Or does the center diff have clutches that force at least 48% of the torque to the front driveshaft no matter what??

AdamIsAdam · **Posted:** Mon Dec 05, 2005 11:53 am

There are two transfer cases. The Part time case is either open or locked. The Full time case has a mode that allows it to act like a posi rear, ie, with clutches. So that case allows for three modes: open, locked, clutches.

so yes, while in Full Time 4WD, it's possible to get stuck with one tire spinning but not as likely, because you'd have the clutches in the t-case trying to divert power to the other axle.

This is all why you want to be in PART TIME 4WD before you get stuck, as someone said earlier.

Se7enLC · **Posted:** Mon Dec 05, 2005 3:08 pm

Go 4x4 It! features a nice flash cartoon of the various types of 4WD offered in Jeep models (only Command-Trac and Selec-Trac apply to the liberty, of course). It also has the offroad driving tips book.

Jeep Trail-Rated Challenge Game is a nice flash trivia-game where it sets up a situation and asks what gear you'd use and how you'd drive through it. A fun way to learn about 4wd and offroading (and even a fun way to test skills for the experienced)

FarmDiesel · **Joined:** Thu Sep 15, 2005 8:49 am **Posts:** 132

AdamIsAdam wrote:

There are two transfer cases. The Part time case is either open or locked. The Full time case has a mode that allows it to act like a posi rear, ie, with clutches. So that case allows for three modes: open, locked, clutches.

so yes, while in Full Time 4WD, it's possible to get stuck with one tire spinning but not as likely, because you'd have the clutches in the t-case trying to divert power to the other axle.

This is all why you want to be in PART TIME 4WD before you get stuck, as someone said earlier.

Not exactly correct. In liberties, full time is an open center differential...it will spin just one tire under the right circumstances. Part time locks the center differential. No clutches, no variable power distribution...50% front, 50% rear. It will spin 2 tires (one front, one rear) unless you have traction aiding devices in the axles.

The Liberty doesn't have any of the more sophisticated systems found on Grand Cherokees (Quadradrive, etc.). It uses a good old fashioned 'traditional full time' and 'traditional part time' 4wd system. Again, no clutches, no shifting power. A Liberty with a full time 4wd system, when in part time 4wd, is just like a liberty with a part-time only system...both are locked in part-time, with 50-50 power split (locked center differential).

LibertyCRD · **Posted:** Mon Dec 05, 2005 4:39 pm

Well see, this is what confuses me. I understand the center differential to be an open diff. So the power coming from the engine is just trying to "escape" via the path of least resistance. On dry pavement cruising down the road that will be partially out of each axle. But if you are off road and stick the front axle real good in the mud then it wouldn't turn at all and all the torque would go to the rear axle.

But then if you look at the Jeep website and view the demonstration of Full-Time mode on the Liberty it shows 48%/52% torque split.

So I don't know... Does anyone know for sure what's going on inside these transfer cases?? If it's truly an open diff...then it will be almost worthless except for maybe in light snow on the road.

AdamIsAdam · **Posted:** Mon Dec 05, 2005 4:46 pm

FarmDiesel wrote:

Not exactly correct. In liberties, part time is an open center differential...it will spin just one tire under the right circumstances. Full time locks the center differential. No clutches, no variable power distribution...50% front, 50% rear. It will spin 2 tires (one front, one rear) unless you have traction aiding devices in the axles.

The Liberty doesn't have any of the more sophisticated systems found on Grand Cherokees (Quadradrive, etc.). It uses a good old fashioned 'traditional full time' and 'traditional part time' 4wd system. Again, no clutches, no shifting power. A Liberty with a full time 4wd system, when in part time 4wd, is just like a liberty with a part-time only system...both are locked in part-time, with 50-50 power split (locked center differential).

What you wrote contradicts itself. The first paragraph is backwards. Full time doesn't lock the center diff or you couldn't drive it on pavement. Then later you say when in Part Time, the center is locked.

Full Time allows for slipage in the transfer case to allow for turning. Part Time doesn't. It's locked.

krazz1e · **Posted:** Mon Dec 05, 2005 4:50 pm

adam is right, part time is 50%front 50% rear center diff locked, the front and rear axles are still open stock. try it. full time allows for slippage therefore in a tight turn the power is transferred to the rear.

LibertyCRD · **Posted:** Mon Dec 05, 2005 4:51 pm

Ok, but can the rear get 100% of the power in certain situations when in full-time?? or are there clutches that prevent all the power from going to the rear driveshaft??

Tightwadsjeeper · **Posted:** Mon Dec 05, 2005 5:59 pm

krazz1e wrote:

adam is right, part time is 50%front 50% rear center diff locked, the front and rear axles are still open stock. try it. full time allows for slippage therefore in a tight turn the power is transferred to the rear.

Correct! Part-time locks the front and rear driveshafts together to turn at the same rate.

Now..... if you have open axles front and rear, that means you've really only got one wheel up front getting power, and one wheel in the rear getting power (whichever one spins most freely) but they (the front and the rear tire) turn at the same rate.

If you've got LS or a locker in either axle then you're getting both wheels to turn on that axle, but they're still going to turn at the same rate as any wheel(s) on the other axle that are being powered.

Luis

Eddo · **Joined:** Thu Jul 07, 2005 7:01 pm **Posts:** 1214

My general rule is. If you are worried about slipping and sliding they go into full-time. If you are worried about getting stuck then go into part-time.

FarmDiesel · **Joined:** Thu Sep 15, 2005 8:49 am **Posts:** 132

I'm sorry, you're correct, I confused my part and full time when I typed it. Full time is open center differential, part time is locked center differential.

The important thing to remember, however, is that there are no clutches in the center differential in KJs. It is open. Anytime a single tire slips, all of the power goes to that tire.

The 48/52 split described on the jeep website would be under perfect conditions...just like you have a 50/50 split between the left and right rear tires with an open rear differential and 2wd. But when you encounter slip, the power shifts TO the tire that is slipping. Put the 2wd's right rear tire on ice, and it'll spin furiously while the L tire does nothing. With full time 4wd, in KJs, put any one tire on ice and it will spin furiously while the other 3 do nothing. Of course, there is some traction from the ice, and some driveline friction that causes other wheels to get some power...

But again, no clutches in the transfer case...and no power shifting mechanism in the center differential...until you lock it by putting the t-case in part time.

LibertyCRD · **Posted:** Tue Dec 06, 2005 10:49 am

That's exactly what I wanted to know. Thanks. I am starting to understand this "full-time" thing now. And I won't ever be using it off road again either now that I see how worthless it is for that purpose!

4 part time or 4 full time??

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