Selec-trac vs command-trac

ResponsibleAdult

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You reference a manual transmission paired with Selectrac. I thought we couldn't order that pairing. Am I wrong? (Please say yes...)
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Jeeper

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Well, I see this has been mostly covered by AlexK and JDaPP, I was without good internet over the holidays so didn’t want to reply to Mac’s post until back in the city. Only a few more granular things to add anyways, the gist has been covered.

First to clear up, the Lo range on both CommandTrac and SelecTrac (whether v1 or 2) are all 2.73:1 commonly called 2.72:1 , only RockTrac is 4:1. The JL will get SelecTrac-II / MP3022, therefore it will have 2.73:1 Lo just like CommandTrac. So all Saharas will have the same crawl ratios when otherwise configured similarly. Of course different axles (either due to diesel or aftermarket) will change things as will auto vs manual, but same transmission+axle will give you same Lo range ratio across the board.

Second, beyond the numbering we don’t know if & what refreshes were made to the MP3022 for the JL. At the very least they have added a 4Hi option not found on the Liberty, and added 2H & 4H to the Durangos implementation. Also it’s a physical shifter unlike the other’s toggle switch (Liberty) or rotary dial (Durango), and has a neutral position not pencil/pen/pin activated Neutral button like the others.

The MP3022 has a few benefits for on-road driving in how its wet clutch system is controlled electronically, and can alter it’s FT application torque split electronically if Jeep decides to implement that (haven’t see that as a Liberty or Durango application yet, but it could be hidden in the Durango, as details remain scant), this allows for speed dependant changing of the torque split to improve application at highway speeds, and also to avoid binding at lower speeds. It can also pre-load the system if it detects variations, which helps improve FT engagement to quicken reaction, however, again it’s unknown if it’s implemented in this application. Unfortunately too much is unknown about the JL’s version/implementation at this time, but the mention of a 50/50 split and not variations makes it seem more rudimentary than what is possible with the platform, so fully imolemented capabilities remain a mystery.

To which, we don’t even have enough info on the torque handling capabilities of the MP3022 for the JL’s SelecTrac! However, it should still be pretty good and I am hoping this refresh got a worthy boost to go along with the Wrangler’s more likely uses vs vehicles like the Liberty & Durango. One concern regarding this point, is that while it sounds great that it has lived alongside the Hemi in the Durango the torque multiplication of the Durango transmission is much lower so that the max torque sent to ST-II from first gear would be higher in the JL implementations whether the 2.0T or 3.6L. The JL has provided a nice boost to the 1st gear ratios of both the manual, and especially the Auto, but this also means more torque sent down the system past the transmission. As we don’t even have torque figures for the Durango application, there’s no way of knowing for sure what if this is any better or the same or (unlikely) worse. If it’s offered on the diesel, then I’ll be more reassured about its capabilities in the gasoline applications, because it would be unlikely that they would mate it to the diesel if it were anywhere near the limit in the gasoline applications.

Now speaking of that, the strength differences between the SlecTrac 1 (not used here but mentioned above) were not inherent in the design, but that the basis for the Jeep NV242 was on the non-reinforced models of the NV241, so they would be similar to pre-2008 in strength, and a stronger model was made for the Hummer. The CommandTrac and RockTrac bith received updates improving strength a bit, with RockTrac being even stronger and receiving the OR designation for NV241OR. So the strength between CommandTrac and SelecTrac would be closer together than the RockTrac wiphich is significantly stronger than both. Just being clear that strength wasn’t based on the type but on their targets.

Finally, and somewhat of my concern, while this transfer case is chain driven, the power is sent to the clutch assembly instead of directly to the output shaft, so it uses a sleeve to ‘lock’ the clutches in Part-Time modes (4Hi / 4Lo) so it’s not truly the same as the NV242 SelecTrac-I or NV241(OR) of CommandTrac/(RockTrac) which has the chain driving the shaft directly, so when it’s locked, it’s LOCKED. The sleeve should provide the outward appearance of the same result as the PartTime modes in CommandTrac and RockTrac, but for serious off-roading it may be a challenge and again something where a lot of in-the-field / on-the-trail testing will prove-out its capabilities/worthiness. I would be far more comfortable with the NV242 than the MP3022, knowing that it is more like a CommandTrac with FT4WD tacked on than a different implementation.

For people who are using it for on-road/soft-road and light trail driving it should be more than adequate, but for serious Rock Crawling with large tires then it may be a bit of a weakness, but at that point I’d be expecting that user to be going with the RockTrac or a 3rd party like Atlas anyways if they were concerned about bullet-proof.

Information is still limited on all the specs (similar to the lack of detailed info on the Aisin manual transmission) so hopefully when folks like 4Wheeler etc get a chance to do a deep dive, then more info will come to light.

Even if we never find out any more info, I’m confident enough to go the SelecTrac-II/MP3022 route, but without that info it will always stick in my mind as a consideration/concern.

Just FYI, this was our early SelecTrac thread, but it spent most of it’s early posts talking about the NV242, and only much later did we address the reality (unfortunately for many) that the JL was getting the MP3022 instead, so much of the early thread doesn’t really apply anymore, including the extremely high praise which is reserved more for ST-I than ST-II;

https://www.jlwranglerforums.com/forum/threads/selec-trac-full-time-4x4-4wd-system-discussions.1267/

It may be enlightening or just cloud the issue more for some.
I've read through a bunch of posts and didn't find the answer I was looking for, so....

1) did anyone ever learn what percentage of power is distributed to the front in the Sahara's 4 Hi Auto setting? Is it variable, does it have an upper limit?
2) in PT 4Hi is the torque split 50/50 front and rear? Making the only difference between PT and Auto, the variableness of the split?
3) In both PT and Auto, the left right split of power is controled by the BLD system right? So what is the purpose of the Anti Spin DIfferential Rear Axle? What benefit does that provide and in what modes do you benefit from it?

4) last question, say I'm driving my Jeep and the rain is coming down hard, should I be in Auto 4 Hi? Ok, what about heavy snow on the highway? Thanks for your insights!
 

robaw

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I've read through a bunch of posts and didn't find the answer I was looking for, so....

1) did anyone ever learn what percentage of power is distributed to the front in the Sahara's 4 Hi Auto setting? Is it variable, does it have an upper limit?
2) in PT 4Hi is the torque split 50/50 front and rear? Making the only difference between PT and Auto, the variableness of the split?
3) In both PT and Auto, the left right split of power is controled by the BLD system right? So what is the purpose of the Anti Spin DIfferential Rear Axle? What benefit does that provide and in what modes do you benefit from it?

4) last question, say I'm driving my Jeep and the rain is coming down hard, should I be in Auto 4 Hi? Ok, what about heavy snow on the highway? Thanks for your insights!
I know this does very little to actually answer any of your questions, but since it happened today it's fresh on my mind and I'll share...

I was driving along on a road about 45mph and came to a stop sign. Waited my turn and continued on. Didn't notice anything out of the ordinary but noticed something flashing in the dash cluster. It was the traction-control light going nuts! I knew the road was wet and it was right around 32 degrees, but wasn't overly concerned. Then up in front of me a pickup (F150 I think) going about the same speed as me completely spun out. Ended up fine, they came to a stop on the shoulder while I carefully coasted and kept my distance. I was planning to stop but they took off.

Not sure what all systems contributed to keeping me in control, but I was in 4H Auto and it was completely smooth for me.
 

SecondTJ

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One concern regarding this point, is that while it sounds great that it has lived alongside the Hemi in the Durango the torque multiplication of the Durango transmission is much lower so that the max torque sent to ST-II from first gear would be higher in the JL implementations whether the 2.0T or 3.6L.
Incorrect. The 5.7 Hemi Durango has the same 1st gear (4.71:1) in its 8HP70 as the JL’s transmission
 
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Jeeper

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I know this does very little to actually answer any of your questions, but since it happened today it's fresh on my mind and I'll share...

I was driving along on a road about 45mph and came to a stop sign. Waited my turn and continued on. Didn't notice anything out of the ordinary but noticed something flashing in the dash cluster. It was the traction-control light going nuts! I knew the road was wet and it was right around 32 degrees, but wasn't overly concerned. Then up in front of me a pickup (F150 I think) going about the same speed as me completely spun out. Ended up fine, they came to a stop on the shoulder while I carefully coasted and kept my distance. I was planning to stop but they took off.

Not sure what all systems contributed to keeping me in control, but I was in 4hi Auto and it was completely smooth for me.
Your post made me think of another question... does the Jeep notify the driver when the Auto 4Hi system detects a traction issue? Was the light you saw related to the electronic stability control or was it a light specific to Auto 4hi? Is there a difference?
 

robaw

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Your post made me think of another question... does the Jeep notify the driver when the Auto 4Hi system detects a traction issue? Was the light you saw related to the electronic stability control or was it a light specific to Auto 4hi? Is there a difference?
I had the same thought - as far as I know there is no visual indication that power is actually being sent to the front. All I have seen is the normal traction control light.
 

Arterius2

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Well, I see this has been mostly covered by AlexK and JDaPP, I was without good internet over the holidays so didn’t want to reply to Mac’s post until back in the city. Only a few more granular things to add anyways, the gist has been covered.

First to clear up, the Lo range on both CommandTrac and SelecTrac (whether v1 or 2) are all 2.73:1 commonly called 2.72:1 , only RockTrac is 4:1. The JL will get SelecTrac-II / MP3022, therefore it will have 2.73:1 Lo just like CommandTrac. So all Saharas will have the same crawl ratios when otherwise configured similarly. Of course different axles (either due to diesel or aftermarket) will change things as will auto vs manual, but same transmission+axle will give you same Lo range ratio across the board.

Second, beyond the numbering we don’t know if & what refreshes were made to the MP3022 for the JL. At the very least they have added a 4Hi option not found on the Liberty, and added 2H & 4H to the Durangos implementation. Also it’s a physical shifter unlike the other’s toggle switch (Liberty) or rotary dial (Durango), and has a neutral position not pencil/pen/pin activated Neutral button like the others.

The MP3022 has a few benefits for on-road driving in how its wet clutch system is controlled electronically, and can alter it’s FT application torque split electronically if Jeep decides to implement that (haven’t see that as a Liberty or Durango application yet, but it could be hidden in the Durango, as details remain scant), this allows for speed dependant changing of the torque split to improve application at highway speeds, and also to avoid binding at lower speeds. It can also pre-load the system if it detects variations, which helps improve FT engagement to quicken reaction, however, again it’s unknown if it’s implemented in this application. Unfortunately too much is unknown about the JL’s version/implementation at this time, but the mention of a 50/50 split and not variations makes it seem more rudimentary than what is possible with the platform, so fully imolemented capabilities remain a mystery.

To which, we don’t even have enough info on the torque handling capabilities of the MP3022 for the JL’s SelecTrac! However, it should still be pretty good and I am hoping this refresh got a worthy boost to go along with the Wrangler’s more likely uses vs vehicles like the Liberty & Durango. One concern regarding this point, is that while it sounds great that it has lived alongside the Hemi in the Durango the torque multiplication of the Durango transmission is much lower so that the max torque sent to ST-II from first gear would be higher in the JL implementations whether the 2.0T or 3.6L. The JL has provided a nice boost to the 1st gear ratios of both the manual, and especially the Auto, but this also means more torque sent down the system past the transmission. As we don’t even have torque figures for the Durango application, there’s no way of knowing for sure what if this is any better or the same or (unlikely) worse. If it’s offered on the diesel, then I’ll be more reassured about its capabilities in the gasoline applications, because it would be unlikely that they would mate it to the diesel if it were anywhere near the limit in the gasoline applications.

Now speaking of that, the strength differences between the SlecTrac 1 (not used here but mentioned above) were not inherent in the design, but that the basis for the Jeep NV242 was on the non-reinforced models of the NV241, so they would be similar to pre-2008 in strength, and a stronger model was made for the Hummer. The CommandTrac and RockTrac bith received updates improving strength a bit, with RockTrac being even stronger and receiving the OR designation for NV241OR. So the strength between CommandTrac and SelecTrac would be closer together than the RockTrac wiphich is significantly stronger than both. Just being clear that strength wasn’t based on the type but on their targets.

Finally, and somewhat of my concern, while this transfer case is chain driven, the power is sent to the clutch assembly instead of directly to the output shaft, so it uses a sleeve to ‘lock’ the clutches in Part-Time modes (4Hi / 4Lo) so it’s not truly the same as the NV242 SelecTrac-I or NV241(OR) of CommandTrac/(RockTrac) which has the chain driving the shaft directly, so when it’s locked, it’s LOCKED. The sleeve should provide the outward appearance of the same result as the PartTime modes in CommandTrac and RockTrac, but for serious off-roading it may be a challenge and again something where a lot of in-the-field / on-the-trail testing will prove-out its capabilities/worthiness. I would be far more comfortable with the NV242 than the MP3022, knowing that it is more like a CommandTrac with FT4WD tacked on than a different implementation.

For people who are using it for on-road/soft-road and light trail driving it should be more than adequate, but for serious Rock Crawling with large tires then it may be a bit of a weakness, but at that point I’d be expecting that user to be going with the RockTrac or a 3rd party like Atlas anyways if they were concerned about bullet-proof.

Information is still limited on all the specs (similar to the lack of detailed info on the Aisin manual transmission) so hopefully when folks like 4Wheeler etc get a chance to do a deep dive, then more info will come to light.

Even if we never find out any more info, I’m confident enough to go the SelecTrac-II/MP3022 route, but without that info it will always stick in my mind as a consideration/concern.

Just FYI, this was our early SelecTrac thread, but it spent most of it’s early posts talking about the NV242, and only much later did we address the reality (unfortunately for many) that the JL was getting the MP3022 instead, so much of the early thread doesn’t really apply anymore, including the extremely high praise which is reserved more for ST-I than ST-II;

https://www.jlwranglerforums.com/forum/threads/selec-trac-full-time-4x4-4wd-system-discussions.1267/

It may be enlightening or just cloud the issue more for some.
https://www.extremeterrain.com/everything-about-the-jeep-jl-wrangler.html
http://chryslermedia.iconicweb.com/mediasite/specs/2018_JP_Wrangler_SPqqqbu093eu5bvdt6d69jkbljjo.pdf
http://www.jeep.nc/content/dam/fca/...ication/2019_Jeep_Wrangler_specifications.pdf
Typo?

222.JPG


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eck

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Finally, and somewhat of my concern, while this transfer case is chain driven, the power is sent to the clutch assembly instead of directly to the output shaft, so it uses a sleeve to ‘lock’ the clutches in Part-Time modes (4Hi / 4Lo) so it’s not truly the same as the NV242 SelecTrac-I or NV241(OR) of CommandTrac/(RockTrac) which has the chain driving the shaft directly, so when it’s locked, it’s LOCKED. The sleeve should provide the outward appearance of the same result as the PartTime modes in CommandTrac and RockTrac, but for serious off-roading it may be a challenge and again something where a lot of in-the-field / on-the-trail testing will prove-out its capabilities/worthiness. I would be far more comfortable with the NV242 than the MP3022, knowing that it is more like a CommandTrac with FT4WD tacked on than a different implementation.
This may turn out to be quite prophetic. I'm pretty sure I experienced 4HI Part-time not locking in correctly, ultimately overheating the clutch pack and leaving me stranded.

https://www.jlwranglerforums.com/forum/threads/service-4wd-indicator-during-brief-beach-trip.38474/
 

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command track is simpler, classic for offroad. selec trac is more modern, great for dirt roads, snow on roads.

Theyre both great. They put command track on classic jeeps for a reason.
 
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