Loving select-trac!

[NachoRuby]

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.

Ok. That explains it. I used my STIs for occasional light track duty, including drag, but other than that, mine were just grocery getters and commuters, with the occasional forest road. Cool that you actually wheeled yours off-road!

Sponsored

 

[Pescatoral Pursuit]

Why is select track not available for the diesel?

 

[BearFootSam]

Ok. That explains it. I used my STIs for occasional light track duty, including drag, but other than that, mine were just grocery getters and commuters, with the occasional forest road. Cool that you actually wheeled yours off-road!

Here is a shot of the old girl in jeep territory at the top of cinnamon. That trail seemed to be about the limit with lack of power being the main issue. I had to slip the clutch coming up from Animas Forks and was wishing I had a low range something fierce.

 

[ShadowsPapa]

Why is select track not available for the diesel?

Likely a torque thing. I'd not want the torque of the 3.0 ecodiesel applied to the drive train of my SX4.

 

[jsalbre]

Some technical info that I haven't seen brought up in this thread:

The "old" Selec-Trac with the NP/NV-242 had a planetary center differential in the transfer case allowing "true" all wheel drive with no binding. Putting it in part time mode locked that center differential.

Sadly this awesome transfer case is no longer available.

The current Selec-Trac and Full Time Rock-Trac use the MP3022 transfer case (yes, they both use the same t-case, just with different low range gearing). The MP3022 uses a wet plate clutch to send power to the front axle, varying the slip amount on that clutch depending on how much power the computer thinks it needs to send to the front. There is no differential in this system, so any difference in front and rear axle speeds is accommodated by clutch slip. In Part time mode the clutch is set to 100% duty cycle (fully engaged). The pros to this transfer case are the ability to vary the amount of torque sent forward, and improved fuel economy when it doesn't need to send anything. The cons are that it's not always engaged, and some people have found that extensive running in loose sand causes this tease to overheat and refuse to engage the clutch.

 

[NCIC105]

Ok so the Old Fart has a question. Coming from old school. 4H 4L. What is the difference in 4 auto and 4 part time?

 

[jsalbre]

Ok so the Old Fart has a question. Coming from old school. 4H 4L. What is the difference in 4 auto and 4 part time?

4 part time is what you're used to. 2wd on the road and 4wd hi or low range on slippery surfaces.

4 auto or 4 full time are designed to allow you to drive on pavement in 4wd, allowing a difference in front and rear axle speeds by way of a center differential or clutch. The advantage to this is in frequently changing conditions, like a partially snow or ice covered road.

 

[Sandevino]

Some technical info that I haven't seen brought up in this thread:

The "old" Selec-Trac with the NP/NV-242 had a planetary center differential in the transfer case allowing "true" all wheel drive with no binding. Putting it in part time mode locked that center differential.

Sadly this awesome transfer case is no longer available.

The current Selec-Trac and Full Time Rock-Trac use the MP3022 transfer case (yes, they both use the same t-case, just with different low range gearing). The MP3022 uses a wet plate clutch to send power to the front axle, varying the slip amount on that clutch depending on how much power the computer thinks it needs to send to the front. There is no differential in this system, so any difference in front and rear axle speeds is accommodated by clutch slip. In Part time mode the clutch is set to 100% duty cycle (fully engaged). The pros to this transfer case are the ability to vary the amount of torque sent forward, and improved fuel economy when it doesn't need to send anything. The cons are that it's not always engaged, and some people have found that extensive running in loose sand causes this tease to overheat and refuse to engage the clutch.

The mechanical linkage in the transfer case is ONLY to the rear wheels be it 2.72:1 (Command-Trac) or 4:1 (Rock-Trak). In 4H all transfer cases are the same and in 4L the reduction occurs. The fatal flaw with the Selection-Trac II is the heat build up within the wet clutch powering the front axle.

 

[NCIC105]

4 part time is what you're used to. 2wd on the road and 4wd hi or low range on slippery surfaces.

4 auto or 4 full time are designed to allow you to drive on pavement in 4wd, allowing a difference in front and rear axle speeds by way of a center differential or clutch. The advantage to this is in frequently changing conditions, like a partially snow or ice covered road.

Thank you.

 

[jsalbre]

The mechanical linkage in the transfer case is ONLY to the rear wheels be it 2.72:1 (Command-Trac) or 4:1 (Rock-Trak). In 4H all transfer cases are the same and in 4L the reduction occurs. The fatal flaw with the Selection-Trac II is the heat build up within the wet clutch powering the front axle.

I'm not sure if you're agreeing with me or disagreeing with something I said.

 

[Sandevino]

I'm not sure if you're agreeing with me or disagreeing with something I said.

Ha... rereading my post I can see how it's confusing. I agree with your points.

Having seen a few of these rebuilt in the 392 Rubicon's they are a bit of a stinker giving the owner a false send of ruggedness.

 

[ShadowsPapa]

In Part time mode the clutch is set to 100% duty cycle (fully engaged). The pros to this transfer case are the ability to vary the amount of torque sent forward, and improved fuel economy when it doesn't need to send anything. The cons are that it's not always engaged, and some people have found that extensive running in loose sand causes this tease to overheat and refuse to engage the clutch.

The problem would seem to be only in auto mode in sand. Lock it together like you would any other transfer case.
This one has been around for a while. 14 years I believe.

BTW- you can monitor the transfer case operation in JSCAN. It operates differently than many would assume.

 

[Erievon]

Bringing this old thread back, has a lot of good info.

Dealer finally waved enough money under my nose to surrender my 20JTONE for a 23 JTR, pick it up this coming saturday. It comes with the RockSelec whatever you wanna call it 4 auto. Wasn't shopping for that, but it's there so...bonus I guess. Came to this thread trying to decide how I am going to use it.

So, does the FAD stay engaged waiting for the torque hit from the clutch when you're in 4 auto? Or does it even have a FAD?

Was thinking I'd leave it in 2H, only using 4auto for bad rain storms or cold weather with potential snow and or ice, and 4H for sand, dirt, and other off-road excursions as I normally would.

 

[ShadowsPapa]

Bringing this old thread back, has a lot of good info.

Dealer finally waved enough money under my nose to surrender my 20JTONE for a 23 JTR, pick it up this coming saturday. It comes with the RockSelec whatever you wanna call it 4 auto. Wasn't shopping for that, but it's there so...bonus I guess. Came to this thread trying to decide how I am going to use it.

So, does the FAD stay engaged waiting for the torque hit from the clutch when you're in 4 auto? Or does it even have a FAD?

Was thinking I'd leave it in 2H, only using 4auto for bad rain storms or cold weather with potential snow and or ice, and 4H for sand, dirt, and other off-road excursions as I normally would.

Yes, it has FAD like any of the others.
Yes, it must be connected any time you are in 4HA because the clutches are applied at times you'd never expect - such as when sitting at a stop light. Then as you apply throttle, the clutches relax until a certain throttle percentage is reached.

Also, if you start off, then nail it, wheel slip or not, there's heavy t-case clutch application -

The FAD has to be engaged all the time it's in 4H Auto.
It can be shown that the clutches are partially applied under a variety of circumstances, so it has to be locked in "AWD". That wouldn't work with an open FAD

The MPG difference is miniscule - I can't recall anyone showing anything worth noting.

I don't see much point in 4H Auto on dry, normal drives on pavement, in town and so on.
The only thing is that if it's like the 4xe, torque may be limited if you really want to nail it hard and jump out into traffic - the torque is NOT limited with the 4xe if it's in 4H auto. It just GOES.

 

[Erievon]

Fantastic info, thanks Papa! That makes sense to me, it has to be ready to engage at any moment, so having to lock the FAD at the same time would be more lag.

Really interesting that it's sitting there ready to pounce when you're at a complete stop, so it reacts by easing off, not scrambling to lock if you stab it from a dead stop.

Sponsored