Explanation of the Command trac and select trac

[billy]

how hard would it be to swap in a select trac transfer case

 

[sevenhelmet]

Billy:
http://www.jeepkj.com/forum/showthread.php?t=32339&highlight=transfer+case

As for the fuel economy of 4WD, I noticed a decrease of about 2 MPG in my Dad's WJ which had full time 4WD. I doubt anyone's driven long enough in 4PT to get a good MPG assessment, and the conditions in which you drive (ice, snow, mud, rocks) will definitely affect your mileage a lot more than simply what drive mode you're in.

 

[Frank]

''Shift-on-the-Fly at speeds up to 88 km/h (55 mph)''

is it the same thing to engage the 4full-time, from 4part-time to 4full-time ?

 

[HoosierJeeper]

''Shift-on-the-Fly at speeds up to 88 km/h (55 mph)''

is it the same thing to engage the 4full-time, from 4part-time to 4full-time ?

Yep....shift on the fly up to 55, on all modes, except to N and 4lo, and from N and 4l0. But it's safe to switch from 2wd to 4hi vise versa, and 2wd to 4 full time...

 

[chuckles]

Am I the only one who thinks they way this is identified on the shifter handle / dash is confusing? Ive owned 4x4 trucks my whole life so ive im used to a shift pattern that is as such

2hi
4hi
N
4lo

This is what my liberty's handle says as well but when I pull it from 2hi into 4hi it says "part time" on my dash. That would almost indicate to guy like me that its in one of those "Part time 4wd" kind of vehicles that engages when the wheels slip to wheels that grip. For an old school guy that's not used to 10 versions of a 4x4 system 4wd means 4hi when all the wheels pull equal and 4lo means 4lo for pulling extra torque.

I had a jeep grand Cherokee that had the quadratrac II in it and my shifter lever had 2 (3 if you count N) positions. It was always in AWD like these new SUV's or 4 low if needed. When I would spin a tire the others would kick in automatically.

Guess im just venting and maybe a little confused by Jeeps approach to dash indicators or something. When I first got my jeep early in the month i prob spent 30 mintues trying to find my full time 4hi mode on my shifter because I couldn't get my 4hi indicator to light up on my dash. All I ever got to illuminate was "part time" or LO so I thought it was broke thinking the part time meant it wasn't really in full time 4x4 like my old truck. From reading on here I assume "part time" is really my jeeps 4hi as I know it and I don't have a feature similar to the way my Cherokee was with quadratrac where its going to automatically engage 4wd when you need it. I may be the odd ball but like the control of selecting when my vehicle is in 4x4 or not.

 

[Ocelot]

I owned a 1981 Dodge 1500, its transfer case shift lever had 2H, 4H, N, and 4LO, a part-time light on the dash lit up when anything other than 2H or N was selected. I believe Part Time simply means "do not use all the time".

 

[chuckles]

I believe Part Time simply means "do not use all the time".

After reading this and other posts ive come to realize that's probably also what its meant to indicate .... just kinda backwards thinking for a guy who always had ford and Toyota's that used the more common Hi or Lo indicators on the dash.

 

[CactusJacked]

When all else fails, read the owners manual. lol Even though the manual explains what the transfer case is doing, I spose the part time dash light can confuse some folks.
4x4 operation begins on page 222: Jeep Owners | Download an Owners Manual 2004 - 2011 | Jeep

 

[chuckles]

When all else fails, read the owners manual. lol Even though the manual explains what the transfer case is doing, I spose the part time dash light can confuse some folks.
4x4 operation begins on page 222: Jeep Owners | Download an Owners Manual 2004 - 2011 | Jeep

I did read it but it says "hi" on the lever and in the manual but "part time" on the dash. being I had the Cherokee that was in a sense AWD I was being thrown own by the part time icon. I understand now though. thanks.

 

[CalcityRenegade]

I did read it but it says "hi" on the lever and in the manual but "part time" on the dash. being I had the Cherokee that was in a sense AWD I was being thrown own by the part time icon. I understand now though. thanks.

Command-Trac is a part time 4WD system, Command-Trac should only be driven in 4WD on low-traction surfaces, Selec-Trac has a different transfer case that allows the vehicle to be driven on all surfaces including dry pavement in 4HI, Driving on dry pavement in 4HI with Command-Trac can result is driveline damage.

 

[TwoBobsKJ]

Selec-Trac is a part time 4WD system, Selec-Trac should only be driven in 4WD on low-traction surfaces, Command-Trac has a different transfer case that allows the vehicle to be driven on all surfaces including dry pavement in 4HI, Driving on dry pavement in 4HI with Selec-Trac can result is driveline damage.

NO!!!! You've got it backwards...

The SelecTrac case IS a Full Time T-case and can be run in 4WD Full Time on any road surface 12 months a year if you so choose. It is essentially an All Wheel Drive system in another name. Put it in Part Time and it functions just like the Command Trac by locking the front and rear axles together.

The Command Trac is a Part Time case. It should only be run in 4HI on slippery surfaces - and a wet road does NOT count as slippery.

Bob

 

[CactusJacked]

Yes, a wet road does count as slippery, and I've driven a many slippery wet roads.
Per the owners manual for what not to do (in bold):
"When additional traction is required the transfer case 4H
and 4L positions can be used to lock the front and rear
driveshafts together and force the front and rear wheels
to rotate at the same speed. This is accomplished by
simply moving the shift lever to these positions. The 4H
and 4L positions are intended for loose, slippery road
surfaces only. Driving in the 4H and 4L positions on DRY
hard surfaced roads may cause increased tire wear and
damage to the driveline components."

 

[uss2defiant]

From the 1st page,

Do not use 4 Hi on non slippery surfaces

Explanation from Jeep web site:

COMMAND-TRAC™
The Command-Trac™ transfer case is the heart of the Command-Trac™ part-time 4WD system. When engaged, both front and rear driveshafts are locked by a chain and gearset, which always turn at the same speed, forming a single drive unit. This is a rigid connection that does not allow for any differential action between front and rear driveshafts. Normal front-to-rear differences in the turning radii of the wheels (when cornering) are compensated for only through wheel slippage on driving surfaces. This transfer case allows for 2WD, 4WD High-Range and Low-Range as well as Neutral.

2 HIGH:
• Front axle spins freely
• Power sent to rear wheel
4 HIGH:
• Shift-on-the-Fly at speeds up to 88 km/h (55 mph)
• Front and rear drive shafts lock together and rotate at the same speed
• Only use on slippery or loose surfaces
NEUTRAL:
• Use for towing your Jeep ® vehicle behind another vehicle
• Does not require uncoupling driveshafts
4 LO:
• Use for severe off-road situations
• Increases available engine torque by 2.72:1
• Slow speed to 3-5 km/h (2-3 mph), put transmission in Neutral
• Engage 4 LO and return transmission to desired gear

SELEC-TRAC™
The Selec-Trac™ transfer case is the heart of the Selec-Trac™ 4WD system. The difference is its Open-Centre Differential. In the 4 part-time position, this differential is locked and the system operates the same as Command-Trac™. In the 4 full-time position, the centre differential is open and allows the front and rear axles to rotate at different speeds when turning corners on high-traction surfaces or while driving over any kind of road surface. The Selec-Trac™ transfer case delivers the added convenience of not having to shift back-and-forth between 2WD and 4WD.

2 WHEEL DRIVE:
• Front axle spins freely
• Power sent to rear wheels
4 PART TIME:
• High-range, for temporary conditions that require extra traction
• Locks centre differential; all four wheels rotate in unison
• Not to be used on dry pavement
4 FULL TIME:
• High-range, for year-round traction, wet or dry
• Centre differential allows the front and rear axle to rotate at different speeds
NEUTRAL:
• Use for towing your Jeep® vehicle behind another vehicle
• Does not require uncoupling driveshafts
4LO:
• Use for severe off-road situations
• Increases available engine torque by 2.72:1
• Slow speed to 3-5 km/h (2-3 mph), put transmission in Neutral
• Engage 4 LO and return transmission to desired gear

 

[CalcityRenegade]

NO!!!! You've got it backwards...

The SelecTrac case IS a Full Time T-case and can be run in 4WD Full Time on any road surface 12 months a year if you so choose. It is essentially an All Wheel Drive system in another name. Put it in Part Time and it functions just like the Command Trac by locking the front and rear axles together.

The Command Trac is a Part Time case. It should only be run in 4HI on slippery surfaces - and a wet road does NOT count as slippery.

Bob

My apologies, I mixed up the two of them when writing this down, This is what happens when I function without coffee lol.

 

[TwoBobsKJ]

Yes, a wet road does count as slippery, and I've driven a many slippery wet roads...

It only took a couple of times for my driveline to release with a very loud BANG! while in 4HI on a wet road for me to realize that Part Time and wet roads don't mix. But I recognize that your mileage may vary...

Mine's only in Part Time in snow, gravel, sand and mud. Other than that it's 2WD or Full Time

Bob

 

[CactusJacked]

We apparently get a different kind of "wet" roads here. Must be run-off from all the slimy Chicago politicians and bureaucrats.

 

[profdlp]

I would suspect that tires might have something to do with it. My tires slip and slide pretty bad with even a little rain. Someone with better road-holding tires wouldn't.

 

[CactusJacked]

Yeah, there should be a side-note in the owners manual, like "don't use part time in the rain if you have tires like this"....

You must be registered for see images attach

 

[profdlp]

Yeah, those ^^ are on my wish list. I have another list of people I'm going to run over with them once they're installed. :icon_lol:

 

[TwoBobsKJ]

We apparently get a different kind of "wet" roads here. Must be run-off from all the slimy Chicago politicians and bureaucrats.

:happy175::happy175::happy175:

Wish I could say you've got the market cornered on slimy politicians, but our Northern Ohio group has left a fair share of slippery "stuff" around here. Jimmy Dimora comes to mind, right ProfDlp? :emotions34:

Bob