Full time 4WD for Intermittent Snow

[treillw]

I am planning on order a JLU. I have a question about the 4:1 Rock-Trac® Heavy-Duty Full-Time 4WD System. As you probably know, this option changes your transfer case to have the following options:

Selec-Trac (or Rock-Trac FT on the Rubicon) has 5 positions on the T-case shifter instead of the standard T-case's 4:
*2H (Two-Wheel Drive High Range)
*4H AUTO (Four-Wheel Drive Auto High Range) <-- This one is unique to the Full Time transfer cases
*4H PT (Four-Wheel Drive Part Time High Range)
*N (Neutral)
*4L (Four-Wheel Drive Low Range)

I live in Montana and depending on which road you drive on, it may be covered in snow and hardly plowed, or it may be plowed and dried out in the sun.

I believe that if you don't have the 4h auto mode, you would constantly have to be shifting your transfer case into 2H when you hit dry pavement to avoid possibly damaging the drivetrain. Is this correct?

At what speed can you shift from 2h to 4h PT in a standard transfer case with the jeep?

If I am understanding this correctly, I probably want the 4h auto Tcase. Our current vehicles basically live in 4auto in the winter.

Just wanted to double check because I'm crazy.

Thanks!

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[Vinman]

I live a few hour's straight north of Montana so see similar road conditions as you. I have a Rubicon with the auto 4wd t-case and absolutely love it, slip it in 4 high auto in the Fall and back to 2 high in the Spring. Typically don’t touch that lever all Winter unless hitting trails.

 

[aldo98229]

Yes, you don’t want to be in PT 4H on bare roads.

PT 4H is supposed to be shift-on-the-fly, but I take that with a grain of salt, especially at speed.

Having owned multiple Jeeps with Command-Trac, Rock-Trac (PT) and Selec-Trac, the latter is the only one that slides right into 4H (Auto) consistently, at speed, without any risk. Still, I wouldn’t shift into it above 50 MPH. Once engaged, you can go as fast as you want.

 

[blueweb]

I don't think this video will answer all your questions, but this gives you a visual demonstration of what the difference is between the 4Hs.

 

[thance]

Owners manual recommends being below 40mph to engage part-time and says the faster you go the more difficult it becomes.

My jeep commander has full time 4wd and it it great on the roads in bad weather - snow/ ice/ slush. For the extra 600 you won't regret it and i haven't heard of anyone that considered it, has it, and wishes they didn't.

There are the die hard that will tell you real men don't need it but outside of that everyone loves it and it will make your life easier and safer.

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