How do I test the front wheel drive?

[Cpt Marvel]

I want to make sure it works before I need it. Now for you knuckledragginleadpaintchipeatindevelopmentallychallengedprimates who just want to say "Hell take it out in the mud boy!": 1. There ain't no mud around here and 2. That's the point of checking it. I don't want to find out it DONT work by getting stuck! Now, when I engage it into 4 high and 4 low and make tight turns, it does give me jerking in the steering. Indicating that is LIKELY working in front. (I've noted that these puppy's have a NICE tight turn radius). But I've also learnt from experience that don't mean both front axles are engaged under load. Can u just put all 4 corners in Jack stands and check it like that? Once again, the wheels may turn but they're not under load.

 

[LibertyTC]

If you have engaged it and feel it binding/jerking at all in turns its working.
What year is ur jeep does it have auto transmission w command trac or Selec-trac? Owners manual has good info too.
Command trac is particular & to be only used on slippery surfaces, grass-mud, gravel snow etc. Turning or driving on dry pavement with command trac not recommended.
The basic theory is with auto transmission, is put into Neutral first then engage any 4WD mode, and return auto stick to drive or a lower gear if necessary.
I like to be moving slightly forward, with auto in neutral, then reach into a 4WD mode then auto trans back into gear, as I have command trac.
Also coming down or out of a 4WD mode auto trans in neutral, down with level into 2WD and return auto to drive.
Anyways...here is a good read... Link:
http://www.jeepkj.com/forum/f196/4wd-use-question-57373/

 

[M38 Bob]

Got a jack? Engage 4wd, roll it forward/reverse a few feet, then jack up a front wheel and see if you can turn it.

Bob

 

[Cpt Marvel]

That link had good info. Thanks

 

[Cpt Marvel]

If you have engaged it and feel it binding/jerking at all in turns its working.
What year is ur jeep does it have auto transmission w command trac or Selec-trac? Owners manual has good info too.
Command trac is particular & to be only used on slippery surfaces, grass-mud, gravel snow etc. Turning or driving on dry pavement with command trac not recommended.
The basic theory is with auto transmission, is put into Neutral first then engage any 4WD mode, and return auto stick to drive or a lower gear if necessary.
I like to be moving slightly forward, with auto in neutral, then reach into a 4WD mode then auto trans back into gear, as I have command trac.
Also coming down or out of a 4WD mode auto trans in neutral, down with level into 2WD and return auto to drive.
Anyways...here is a good read... Link:
http://www.jeepkj.com/forum/f196/4wd-use-question-57373/

It's an 03.

 

[tommudd]

It's an 03.

But which transfer case?
on the handle does it have
2WD, PART TIME 4WD, FULL TIME 4WD, N,4 LOW ( Select Trac )
OR
2WD, PART TIME 4WD, N, 4 LOW ( Command Trac)

??:shrug:

 

[TwoBobsKJ]

And for the record, just because 4WD is engaged does NOT mean that all for wheels are 'locked' together and will spin equally in slippery conditions.

Each axle has a differential that 'differentiates' the speed of the wheel on each axle as necessary. In other words, in 2WD the wheels on the rear axle will spin at different speeds in a turn; engaging 4WD doesn't change that. One wheel will spin faster as necessary in a turn and in slippery conditions the wheel with LESS traction will spin. If we had the capability of engaging the front axle by itself - without the rear axle engaged - it would operate the same way. In a turn the wheel on the outside of the turn spins faster; in slippery conditions the wheel with LESS traction will spin.

With the CommanTrac transfer case, when in 4WD (either High or Lo) the front and rear axles are locked together; there is no differentiation between the speed of the faster moving wheel on the rear axle and the next-faster wheel on the front (unless you're going in reverse a rear wheel will always travel further/faster than a front wheel since it "trails" the turn of the front wheels.) That's why there's driveline binding when you're in PART TIME 4WD on the CommanTrac on dry pavement - the outside rear wheel is trying to spin faster than the outside front wheel but the transfer case keeps them spinning at the same speed. There's a very real danger the transfer case could be broken if you do repeated turns on dry pavement while in 4HIGH (Part Time.)

So unless you have a locker on the front and rear diffs, at best you will only have one wheel on each axle "engaged" in slippery conditions.

The SelecTac transfer case has a differential in the case that is engaged when in 4WD Full Time - in essence it functions as an AWD vehicle. It can be driven on any surface because it differentiates the speed between the front and rear axles; the outside rear wheel is allowed to spin faster than the outside front wheel. Handy when going from snow-covered to dry pavement during the winter. Just leave it in Full Time all of the time and forget it.

Long answer to your short question, Capt. Marvel. If you're feeling binding when on dry pavement while in 4WD Part Time then the front axle is engaged. Just don't do that anymore or you may break it :waytogo:

Now if you have the SelecTrac Full Time transfer case, pull the handle up to the Full Time position and drive it that way all you want.

Bob

 

[dude1116]

If you have engaged it and feel it binding/jerking at all in turns its working.
What year is ur jeep does it have auto transmission w command trac or Selec-trac? Owners manual has good info too.
Command trac is particular & to be only used on slippery surfaces, grass-mud, gravel snow etc. Turning or driving on dry pavement with command trac not recommended.
The basic theory is with auto transmission, is put into Neutral first then engage any 4WD mode, and return auto stick to drive or a lower gear if necessary.
I like to be moving slightly forward, with auto in neutral, then reach into a 4WD mode then auto trans back into gear, as I have command trac.
Also coming down or out of a 4WD mode auto trans in neutral, down with level into 2WD and return auto to drive.
Anyways...here is a good read... Link:
http://www.jeepkj.com/forum/f196/4wd-use-question-57373/

For our T-cases you don't need them in neutral unless engaging 4-LO

 

[uss2defiant]

I'm going to ask my questions here since I have a 2003 as well.
there's a dirt lot right by my complex which seemed loose enough to test the 4wd functionality by driving in a tight radius. I am totally new to 4wd and have no experience what so ever. However, I've done my reading and understand what should be happening, I think.

My test was driving in a counter clockwise circle.


A few questions:
1. In 4 Lo I can feel the rear driverside skipping to catch up w/ the outside tire speed. In 4 Part time I do not feel that. Shouldn't I feel that happening as well in 4PT since 4Lo is also "part time" as well?

2.I noticed that going from 4 Lo to 4 FT, it feel the tire skipping as though it was still in Part time mode. I had to drive straight for a little bit to get it to disengage. Is this an issue??

Thanks.

 

[TwoBobsKJ]

I'm going to ask my questions here since I have a 2003 as well.
there's a dirt lot right by my complex which seemed loose enough to test the 4wd functionality by driving in a tight radius. I am totally new to 4wd and have no experience what so ever. However, I've done my reading and understand what should be happening, I think.

My test was driving in a counter clockwise circle.


A few questions:
1. In 4 Lo I can feel the rear driverside skipping to catch up w/ the outside tire speed. In 4 Part time I do not feel that. Shouldn't I feel that happening as well in 4PT since 4Lo is also "part time" as well?

In 4LO you're more likely to feel it since you're going slower and there is more torque going to the wheels thanks to the lower gearing. I'm sure you're feeling the wheelspin thanks to the lower speed at which you're driving in a circle.

2.I noticed that going from 4 Lo to 4 FT, it feel the tire skipping as though it was still in Part time mode. I had to drive straight for a little bit to get it to disengage. Is this an issue??

Thanks.

The SelecTrac needs a couple of moments for the clutches to release and transition from LO to FT or from FT to 2WD. I typically let off the throttle when shifting and then 'goose it' lightly to complete the shift.

Bob

 

[uss2defiant]

Thanks Bob,

looks like I can now focus solely on upgrades now.
whew.....