Loving select-trac!

[SpeedNeed]

I have just been leaving it in 4 Auto in case of some unlikely safety advantage. Not sure what it‘s costing me in mpg. Do any of the screens or lights tell you when it’s automatically engaged 4WD?

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[dcmdon]

You are probably doing the smartest thing. I don't notice any mileage difference, but it must be there. Ha.

I'm not sure it offers a safety advantage, but it can't hurt.

 

[UnforseenWeather]

Selec-trac was a huge feature on my Mojave that I wanted. I had an older truck with 2 or 4 wheel drive. I loved having AWD in my new-style Cherokees and they were great in snow and mixed conditions… I wanted the new truck to have great capability, and it does. My Mojave with Selec-trac might be the best all-season vehicle I’ve ever had.

 

[NachoRuby]

Selec-trac was a huge feature on my Mojave that I wanted. I had an older truck with 2 or 4 wheel drive. I loved having AWD in my new-style Cherokees and they were great in snow and mixed conditions… I wanted the new truck to have great capability, and it does. My Mojave with Selec-trac might be the best all-season vehicle I’ve ever had.

Username checks out. you were made for selec trac, or vice versa

 

[dcmdon]

My Mojave with Selec-trac might be the best all-season vehicle I’ve ever had.

My Jeep was great in the snow. Unfortunately I couldn't keep up with my wife last winter in her Volvo with Michelin Ice-X winter tires.

My local dealer is waiting on me to bring in my wheels for some Nokian LT3s. I'll be damned if I'm going to watch her walk away from me on the highway in a snow storm. ha.

Though I do have to say that the OEM Falken ATs were surprisingly good. Lots of sipes gives it away.

 

[Blade1668]

I was going to install a 242 T-case in my MJ before I moved to AL but someone decided to take my Jeep parts stash before I could get them moved to AL from GA. I had bought and stripped down a XJ with that for my MJ, dang nice to have in winter.

 

[Blade1668]

The Comanche wasn't really sure-footed on slick or snowy roads. It would get through but you had to watch it with the light ass-end and no full-time.
The Eagle -you couldn't get that thing stuck unless you high-centered it and talk about sure-footed.

IMO, rain slick roads are where they really shine. Our Grand Cherokees, all versions, were no problem in any rain, even when the low spots in the road filled with rain - you would feel like you hit a wall or something but it would go through if you hung on, and you'd not slip or slide.

No joke about the MJ's and wet, snow / ice on roads spit on pavement and my MJ would break traction unless it had a load in the bed. Another reason I kept four 5 gal fuel cans and toolbox in bed most of the time.

 

[jac04]

Do any of the screens or lights tell you when it’s automatically engaged 4WD?

The dash will indicate if you are in 4AUTO mode, but as far as I know there is no other light telling you if the Selec-Trac has actually send any power to the front wheels.

 

[Lunentucker]

What would it take to retrofit Selec-trac into a truck that doesn't have it? Transfer case, axles, sensors?

 

[jac04]

My Jeep was great in the snow. Unfortunately I couldn't keep up with my wife last winter in her Volvo with Michelin Ice-X winter tires.

My local dealer is waiting on me to bring in my wheels for some Nokian LT3s. I'll be damned if I'm going to watch her walk away from me on the highway in a snow storm. ha.

Though I do have to say that the OEM Falken ATs were surprisingly good. Lots of sipes gives it away.

I agree, the AT3Ws are really good in the snow combined with Selec-Trac. This winter, I'm going to try a set of JLR take-offs with KO2s as my winter tires.

I've had lots of AWD vehicles over the years, all running dedicated snow tires (my favorites being General Altimax Artics). My favorite snow car of all time was my 2006 Subaru Legacy wagon (regular wagon, not the outback version). With a 5-speed manual and no traction control, that car always did exactly what I wanted it to.

IMO, the Selec-Trac is good in the snow, but it just can't match the capabilities of a 'real' AWD system.

 

[BearFootSam]

Coming from a MT forester that I put an Ausie locker in, that car was unstoppable in snow but having to constantly keep after tire pressures to the n'th degree or risk blowing out the viscous coupling was a headache. Does the jeep system have a similarly low tolerance for tire pressure / circumference mismatch as the Subaru VC system? Despite diligent attention my VC went bad at 62k miles. Having replaced that expensive piece of hardware and several CV axles led me to seeking out the part-time Rock-Trac system specifically to get the most robust setup.

 

[NachoRuby]

Coming from a MT forester that I put an Ausie locker in, that car was unstoppable in snow but having to constantly keep after tire pressures to the n'th degree or risk blowing out the viscous coupling was a headache. Does the jeep system have a similarly low tolerance for tire pressure / circumference mismatch as the Subaru VC system? Despite diligent attention my VC went bad at 62k miles. Having replaced that expensive piece of hardware and several CV axles led me to seeking out the part-time Rock-Trac system specifically to get the most robust setup.

What year was that Forester? Never had that issue with a WRX and two STIs, and a whole lot of miles. In fact, I always thought it was a bigger issue on jeeps, with no center diff. But I've never had a 4wd issue on a jeep either.

 

[ShadowsPapa]

Coming from a MT forester that I put an Ausie locker in, that car was unstoppable in snow but having to constantly keep after tire pressures to the n'th degree or risk blowing out the viscous coupling was a headache. Does the jeep system have a similarly low tolerance for tire pressure / circumference mismatch as the Subaru VC system? Despite diligent attention my VC went bad at 62k miles. Having replaced that expensive piece of hardware and several CV axles led me to seeking out the part-time Rock-Trac system specifically to get the most robust setup.

AMC used the then brand new NP transfer case with the viscous coupling in the Eagle. Yes, they'd "blow out" now and then but the bigger issue was the design, the play in the t-case. An expert I know on Jeep transfer cases said they used to take brand new ones apart and machine the housings and put in thrust bearings instead of washers and take out play and they'd last much better.

There's no tire pressure issue I'm aware of - you'd have to be way off to have any sort of issue, and I mean WAY off because of how that coupling works.
When there's a slight difference in speed between the front and rear drive shafts, the silicone fluid acts like a liquid and allows sheer without problem. It acts thin like a liquid.
It's only when the speed difference is high that it acts thick and resists sheer and starts to grip forcing the speed difference to be minimal.
Tire pressure differences, such as 35 on one end and 38 on the other axle ain't enough to be any issue. If it was, Eagles would have blown transfer cases left and right as few people even realized there was a problem until a tire LOOKED low. There was no TPMS.
In fact, the tire pressure sticker in the glove box tells you to run about 2 psi more in the front tires than the rear due to the weight of the front end of those case.
There's never been any talk of issues with that coupling due to tire pressure - and for good reason - it won't matter, the rolling diameter difference would be minimal especially if you consider that one tire on that axle is still likely spinning the same rpm as the other 2 tires, making the difference in rolling diameter even smaller. You'd have to run both tires on the same axle really low to matter at all - more than 3 or 4 psi difference.

I've only ever had transfer case issues with one Eagle or Jeep I've owned over the years and that was in the SX4 I have now. It went about 160,000 miles and I noticed suddenly it was more like a 2wd car with the slightest amount of slick. I decided to service the t-case and check things out.
I knew instantly when the fluid started to drain. It should have been a nice red and smelled like ATF. Instead it was a muddy brown and stunk to high heaven - the coupling had blown. No parts so I started looking for a used transfer case to put in it. Instead I landed a NOS NP transfer case of the correct model, still in the crate, for a bit over $300 - and it's been perfect since. Very stable and sure-footed again.

Anyway, small tire pressure differences won't matter on those couplings because the minor speed difference is allowed for in the fluid in the coupling. they ONLY grip with larger differences like a spinning wheel. 2 or 3 psi is nothing. It won't even get warm with that.

 

[ShadowsPapa]

What year was that Forester? Never had that issue with a WRX and two STIs, and a whole lot of miles. In fact, I always thought it was a bigger issue on jeeps, with no center diff. But I've never had a 4wd issue on a jeep either.

You won't. Tire pressures would would have to be severely off to matter at all. Those couplings don't begin to care unless there's a large speed difference between drive shafts.
If one tire is low, and the other tire on that same axle isn't, then the speed difference is really small at the drive shaft because it's split between the two tires on that axle.
I've lost track of the Grand Cherokees we've owned, and I've had several Eagles with the NP transfer case with that coupling. Even to this day with those cars being 40 years old, transfer case issues aren't talked about much at all.

What would it take to retrofit Selec-trac into a truck that doesn't have it? Transfer case, axles, sensors?

It's been looked into -
Wiring harnesses, PCM, ABS module and more (I can't recall if the TCM was involved or not).
Action is handled by the ABS sensing the speed differences and interacting with other modules.
It's all electronic so it's not a matter of swapping hard parts only.
A member looked into it a while back and it would be a massive project, very expensive and possibly even not possible due to the software involved. Every module has to match security-wise so it's not just a matter of popping in a different module.

 

[BearFootSam]

What year was that Forester? Never had that issue with a WRX and two STIs, and a whole lot of miles. In fact, I always thought it was a bigger issue on jeeps, with no center diff. But I've never had a 4wd issue on a jeep either.

It was a 2018. To be fair I worked it hard. I don't think too many foresters with RTT make it over cinnamon pass.

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