Selec-Trac full time 4x4 4WD system discussions

The Great Grape Ape

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WXman

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Selec-Trac!!! BEST t-case ever offered!!!

Now I gotta' have one!!
 
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freegld

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It was wishful thinking on part to hope for a rear locking differential on the Sahara instead of LSD, especially if you get the Selec-Trac T-case.
 

AZJim

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Three cheers for the selec trac. Have that in my 2002 Grand Cherokee. Hopefully it's the same unit or as good.
I suspect by offering it in the Sahara trim at first is just to test the waters, see what the take rate is. High enough demand
should see it being offered in other trims.
I've been thinking about the Sahara anyway.

Jim
 

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Can someone explain why the Select Trac is only on Sahara but not Rubicon? Maybe the Rubicon will come with this standard?
 
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Can someone explain why the Select Trac is only on Sahara but not Rubicon? Maybe the Rubicon will come with this standard?
So Milous PLEASE chime in and clarify, is the select trac standard on Sahara but available as an option on other trims?
Not 100% on this yet, but the latest info we have is:
  • Sport and Sahara will get Command-Trac as standard
  • Sahara will get Selec-Trac as an option
  • Rubicon will get Rock-Trac
 
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ModdedJK

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The Selec-Trac full time 4x4 is a nice surprise!

Only downside is you can't use a front auto locking differential with it.
 
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The Great Grape Ape

The Great Grape Ape

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This sounds interesting. Sounds like Rock-Trac is just a more hardcore version. :like:
Nah, the reason the Rubi gets the RockTrac is because it's still a 4:1 ratio, Command Trac and Select-Trac are both 2.7:1 ratio with no other option currently. So it does make sense to Have full blown RT on Rubicon

Hopefully Select-Trac is offered on other 'special editions', because I want a more stout 'Sahara' if that's all it's limited to, something like the BackCountry or Chief, where you get nearer a Rubi without the 4:1 and without the Swaybar disco, though I'd love both too, but will sacrifice for Select-Trac for better manners in Winter.
 

Vegas_Sirk

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Nah, the reason the Rubi gets the RockTrac is because it's still a 4:1 ratio, Command Trac and Select-Trac are both 2.7:1 ratio with no other option currently. So it does make sense to Have full blown RT on Rubicon

Hopefully Select-Trac is offered on other 'special editions', because I want a more stout 'Sahara' if that's all it's limited to, something like the BackCountry or Chief, where you get nearer a Rubi without the 4:1 and without the Swaybar disco, though I'd love both too, but will sacrifice for Select-Trac for better manners in Winter.
Is there a down side to the 4:1 ratio?
 
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The Great Grape Ape

The Great Grape Ape

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Is there a down side to the 4:1 ratio?
Not really. Unlike your Axle ratio, it's only 4:1 in 4Low, and really IMO that gives you much better control for the 4Lo stuff.
Now the one possible drawback is if you like to drive 'somewhat quicker' in 4lo , especiallylocked, in which case you get about 10+ MPH from the 2.72:1 vs the 4:1, this is rare, and really only for people who know how this is useful (most people should use 4Lo for crawling or descending, not 20+MPH) you can definitely strain things at those speeds if you do not know what you are doing and especially do it for a long period.

Axle ratios give up efficiency for performance, but this is a limited use. Now you can work the system against it's axle limitation in that a Rubicon with stock 'lesser' 3.73 axles will still have a better crawl ratio than a Sahara with upgraded 5.38 axles. So you can keep off-road prowess but give back some highway efficiency with a better transfer case ratio, but the axle will still affect acceleration while the T-case doesn't, so there's still that in the bigger picture.

The 3:73 Rubi was my old rig, because the 3.73 axle also had less of a tendancy to slip in wet/icey winter intersection, etc, But when needed off-road I could always dial it up with the RockTrac.
 

Vegas_Sirk

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Not really. Unlike your Axle ratio, it's only 4:1 in 4Low, and really IMO that gives you much better control for the 4Lo stuff.
Now the one possible drawback is if you like to drive 'somewhat quicker' in 4lo , especiallylocked, in which case you get about 10+ MPH from the 2.72:1 vs the 4:1, this is rare, and really only for people who know how this is useful (most people should use 4Lo for crawling or descending, not 20+MPH) you can definitely strain things at those speeds if you do not know what you are doing and especially do it for a long period.

Axle ratios give up efficiency for performance, but this is a limited use. Now you can work the system against it's axle limitation in that a Rubicon with stock 'lesser' 3.73 axles will still have a better crawl ratio than a Sahara with upgraded 5.38 axles. So you can keep off-road prowess but give back some highway efficiency with a better transfer case ratio, but the axle will still affect acceleration while the T-case doesn't, so there's still that in the bigger picture.

The 3:73 Rubi was my old rig, because the 3.73 axle also had less of a tendancy to slip in wet/icey winter intersection, etc, But when needed off-road I could always dial it up with the RockTrac.
Interesting. Yea I will not likely be in 4 Lo all that often due to the fact I am doing more Overlanding then crawling. My use is a lot of 4 High, as its driving off road through sand and trails but very little rock crawling. Also HWY is important to me as I will be driving a lot of 5-6 hour road trips to locations. Being in Boise, Idaho I'm road trips away from Bend, OR, Jackson, WY, Yellowstone Park, Salt Lake, UT, Moab, UT, ..... pretty much any interesting place in OR, WA, ID, WY, UT, or MT.
 

NewApexJT

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So I was reading up on the optional select trac transfer case for the Sahara and I saw that it was an electronic shift on the fly system. I thought that people would be up in arms with this as it's more of a casual off road t-case due to it working with clutches and not a chain system; in comparison to the standard t-case. Just curious to see why everyone seems to be excited for it.
 

WaltA

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Nah, the reason the Rubi gets the RockTrac is because it's still a 4:1 ratio, Command Trac and Select-Trac are both 2.7:1 ratio with no other option currently. So it does make sense to Have full blown RT on Rubicon
RockTrac and SelecTrac don't need to be mutually exclusive. The main feature with RockTrac is that the Part Time 4WD Low is a 4:1 ratio (as you mentioned). The SelecTrac still offers a separate Part Time Low setting/mode that while is 2.7:1, could instead be 4:1. Flipping this around, there is no technical reason why RockTrac could not also offer a Full Time 4WD High (1:1) setting/mode.
 

WaltA

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On the issue of no 2-door Sahara, and the SelecTrac transfer case only being offered on the Sahara, reminds me of a talk with the Jeep people at one of the Jeep gatherings several years ago.

When asked why no SelecTrac option on the Wranglers, they mentioned that the 2-door didn't offer enough room in the drive train to accommodate that transfer case. This makes we wonder if their solution (finally!) was to offer SelecTrac in a model of the Wrangler that doesn't come in a short 2-door?
 

Jabs

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Nah, the reason the Rubi gets the RockTrac is because it's still a 4:1 ratio, Command Trac and Select-Trac are both 2.7:1 ratio with no other option currently. So it does make sense to Have full blown RT on Rubicon

Hopefully Select-Trac is offered on other 'special editions', because I want a more stout 'Sahara' if that's all it's limited to, something like the BackCountry or Chief, where you get nearer a Rubi without the 4:1 and without the Swaybar disco, though I'd love both too, but will sacrifice for Select-Trac for better manners in Winter.
What's the difference between RockTrac and Select-Trac? I want a full time 4WD system. Does this mean I have to get a Sahara?
 

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