Questions about Select Trac II

SilverKK09 · **Posted:** Mon Jan 05, 2009 1:58 am

Not a bunch of questions but something that made me think:

supposedly, select trac II lets you use your 4x4 AT ALL TIMES.... (when you switch into 4auto of course) but I wonder:
Will my MPG's be affected?
Should I use it ALWAYS???
if so, why bother on putting a 2wheel drive and 4auto......

Why would I want to drive on 2 wheel drive if this transmission is supposed to work in auto mode?? I can only think about MPG's factors.....

anyhow....... ideas?

unclejjg · **Posted:** Mon Jan 05, 2009 12:06 pm

I'm sure it will affect your mileage in a similar way to how an AWD version of a vehicle gets poorer mileage than a 2WD version (Subaru, RAV4, etc, etc).

I have the Selec-Trac as well, and my opinion is when it is slippery (or just becoming slippery), I'll gladly sacrifice the mileage. I'm not going to be using 4 Auto on a sunny summer day though.

racer1 · **Posted:** Mon Jan 05, 2009 10:03 pm

I think I loose about 1/2 mile to the gallon when using awd. Not nearly as much as the remote start, but my fat cold booty likes it. I live in Minnesota, when it snows I put it in awd and sometimes leave it in for a week, I really don't know why Jeep would sell a part time 4 wheel drive system except in a off road package,(I>E> cheaper to make and could charge a premium for it).

Dave

tjkj2002 · **Posted:** Mon Jan 05, 2009 10:09 pm

racer1 wrote:

I think I loose about 1/2 mile to the gallon when using awd. Not nearly as much as the remote start, but my fat cold @$#% likes it. I live in Minnesota, when it snows I put it in awd and sometimes leave it in for a week, I really don't know why Jeep would sell a part time 4 wheel drive system except in a off road package,(I>E> cheaper to make and could charge a premium for it).

Dave

Because some of us actually take our Jeeps offroad and fulltime 4wd is utterly useless when offroad since it sends all the power to the axle with the least amount of traction and where parttime 4wd has a major advantage since it locks both F/R driveshafts together so they supply equal amounts of torque to the F/R axles for more traction then fulltime can ever supply.

Plus learning how to drive helps drive around in snow/ice in only 2wd,good tires helps also.

unclejjg · **Posted:** Mon Jan 05, 2009 10:49 pm

tjkj2002 wrote:

racer1 wrote:

I think I loose about 1/2 mile to the gallon when using awd. Not nearly as much as the remote start, but my fat cold @$#% likes it. I live in Minnesota, when it snows I put it in awd and sometimes leave it in for a week, I really don't know why Jeep would sell a part time 4 wheel drive system except in a off road package,(I>E> cheaper to make and could charge a premium for it).

Dave

Because some of us actually take our Jeeps offroad and fulltime 4wd is utterly useless when offroad since it sends all the power to the axle with the least amount of traction and where parttime 4wd has a major advantage since it locks both F/R driveshafts together so they supply equal amounts of torque to the F/R axles for more traction then fulltime can ever supply.

Plus learning how to drive helps drive around in snow/ice in only 2wd,good tires helps also.

I could be all wrong, but I respectfully disagree with you. At least the owners manual describes Selec-trac as ordinarily 42% front/58% rear with the ability to send up to 100% of torque to the axle with the most traction. Unfortunately I don't have the manual in front of me to quote it, but if someone wants to look it up, I'm almost positive that is what it says for Selec-Trac. Also the manual mentions that the Low range in the Selec-Trac does infact lock the two axles together...so considering the Low range is most often used for heavy off-roading, I don't see a problem with that transfer case.

Further supporting this is the fact that the Liberator II was a Selec-Trac model. Also, when Jeep did the little off-road excursion found on youtube, the vehicles were Selec-Trac models (as described by at least one article that showed the video). I can't imagine Jeep would modify the less capable model for SEMA and off-road propaganda, or use the less capable model to show case the vehicle's off-road prowess to critics and media.

tjkj2002 · **Posted:** Mon Jan 05, 2009 10:57 pm

unclejjg wrote:

tjkj2002 wrote:

racer1 wrote:

I think I loose about 1/2 mile to the gallon when using awd. Not nearly as much as the remote start, but my fat cold @$#% likes it. I live in Minnesota, when it snows I put it in awd and sometimes leave it in for a week, I really don't know why Jeep would sell a part time 4 wheel drive system except in a off road package,(I>E> cheaper to make and could charge a premium for it).

Dave

Because some of us actually take our Jeeps offroad and fulltime 4wd is utterly useless when offroad since it sends all the power to the axle with the least amount of traction and where parttime 4wd has a major advantage since it locks both F/R driveshafts together so they supply equal amounts of torque to the F/R axles for more traction then fulltime can ever supply.

Plus learning how to drive helps drive around in snow/ice in only 2wd,good tires helps also.

I could be all wrong, but I respectfully disagree with you. At least the owners manual describes Selec-trac as ordinarily 42% front/58% rear with the ability to send up to 100% of torque to the axle with the most traction. Unfortunately I don't have the manual in front of me to quote it, but if someone wants to look it up, I'm almost positive that is what it says for Selec-Trac. Also the manual mentions that the Low range in the Selec-Trac does infact lock the two axles together...so considering the Low range is most often used for heavy off-roading, I don't see a problem with that transfer case.

Further supporting this is the fact that the Liberator II was a Selec-Trac model. Also, when Jeep did the little off-road excursion found on youtube, the vehicles were Selec-Trac models (as described by at least one article that showed the video). I can't imagine Jeep would modify the less capable model for SEMA and off-road propaganda, or use the less capable model to show case the vehicle's off-road prowess to critics and media.

Yes on a flat,straight stretch of road when in fulltime the torque split is about 42/58,until you turn,hit a bump,or "get on it" while on gravel.Then the fulltime option sends torque to the path of least resistance(open diff).The t-case your talking about is the QuadraDriveII which is in the Grands.

It is known that the selecttrac,I or II,is by it's nature slightly weaker then it's commandtrac counterpart.More parts and a fragile center diff to worry about,not that the 3.7 will fry one to easily though,but have fun with the electronic shifter since GM still hasn't gotten them to be very reliable either in the last 15 years.

SilverKK09 · **Posted:** Mon Jan 05, 2009 11:10 pm

ahhhhhh thank God for the lifetime warranty!!!! =)

tjkj2002 · **Posted:** Mon Jan 05, 2009 11:14 pm

SilverKK09 wrote:

ahhhhhh thank God for the lifetime warranty!!!! =)

You sure?

If I'm not mistaken the lifetime powertrain warranty is the same as the 7/70,000 powertrain warranty as far as coverage items and only "internally lubricated" parts are covered.That electric shifter does not fall into that category,but it may be covered,but it may not.Don't rely on the warranty,it may go by-by soon.

E2 · **Posted:** Tue Jan 06, 2009 1:00 am

I did a study of mpg using the 2wd versus the auto 4wd. Could not see really any difference in mpg. I don't see any real reason to use auto 4wd on the road. If this was the case then why is there in option to put it into 2wd?

Boblemoche · **Posted:** Tue Jan 06, 2009 1:14 am

tjkj2002 wrote:

unclejjg wrote:

tjkj2002 wrote:

racer1 wrote:

I think I loose about 1/2 mile to the gallon when using awd. Not nearly as much as the remote start, but my fat cold @$#% likes it. I live in Minnesota, when it snows I put it in awd and sometimes leave it in for a week, I really don't know why Jeep would sell a part time 4 wheel drive system except in a off road package,(I>E> cheaper to make and could charge a premium for it).

Dave

Because some of us actually take our Jeeps offroad and fulltime 4wd is utterly useless when offroad since it sends all the power to the axle with the least amount of traction and where parttime 4wd has a major advantage since it locks both F/R driveshafts together so they supply equal amounts of torque to the F/R axles for more traction then fulltime can ever supply.

Plus learning how to drive helps drive around in snow/ice in only 2wd,good tires helps also.

I could be all wrong, but I respectfully disagree with you. At least the owners manual describes Selec-trac as ordinarily 42% front/58% rear with the ability to send up to 100% of torque to the axle with the most traction. Unfortunately I don't have the manual in front of me to quote it, but if someone wants to look it up, I'm almost positive that is what it says for Selec-Trac. Also the manual mentions that the Low range in the Selec-Trac does infact lock the two axles together...so considering the Low range is most often used for heavy off-roading, I don't see a problem with that transfer case.

Further supporting this is the fact that the Liberator II was a Selec-Trac model. Also, when Jeep did the little off-road excursion found on youtube, the vehicles were Selec-Trac models (as described by at least one article that showed the video). I can't imagine Jeep would modify the less capable model for SEMA and off-road propaganda, or use the less capable model to show case the vehicle's off-road prowess to critics and media.

Yes on a flat,straight stretch of road when in fulltime the torque split is about 42/58,until you turn,hit a bump,or "get on it" while on gravel.Then the fulltime option sends torque to the path of least resistance(open diff).The t-case your talking about is the QuadraDriveII which is in the Grands.

It is known that the selecttrac,I or II,is by it's nature slightly weaker then it's commandtrac counterpart.More parts and a fragile center diff to worry about,not that the 3.7 will fry one to easily though,but have fun with the electronic shifter since GM still hasn't gotten them to be very reliable either in the last 15 years.

there are no center diff in the KK select track. its not the quadradrive II

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=25830

I dont know about the gm shifters but mine (select track) works perfectly. I can get in and out of 2wd 4wd hi 4wd lo while standing still with no problems

nightdrv · **Posted:** Tue Jan 06, 2009 1:17 am

Personally, in this Jeep and the 99 WJ I had, I would only use 4wd when absolutely needed. ie: sand, snow, or climbing slippery terrain. And in the KK, 4wd auto is not something I would use every day. Currently my KK is in 4wd auto, because I want to be able to back it out tomorrow morning when all this ice is done laying down. But seriously, it's hard as heck to turn the steering wheel with 4wd engaged, for obvious reasons. You can always hear the tyres chirping away at even mild turns.

2wd is the way to go, until you need 4wd.

Just my .02 cents.

Boblemoche · **Posted:** Tue Jan 06, 2009 1:23 am

Quote:

But seriously, it's hard as heck to turn the steering wheel with 4wd engaged, for obvious reasons.

I think something is wrong with your KK

I dont notice any difference in the steering wheel in 4wd auto, not even in 4wd low.
the steering will stiffen only if I lock the front axle

BTW is it your KK on your avtar. I see a light bar on top :?:

zoso7374 · **Posted:** Tue Jan 06, 2009 1:34 am

Heres a question that is probably obvious to some here . . . but a mystery to me.

I sometimes pull into my sloped front yard if there are a lot of cars in my driveway, i needed 4wd a couple of times to back out to avoid ripping up the grass when we had some snow. KK backs out easily after slipping in 2WD. But as soon as I hit the pavement, the vehicle seems to 'bind' in reverse. Since I am backing into the road, I need to finish a K turn and get out, but the KK seems like it is resisting my reverse motion even after I flip it back into 2WD. Now I know that it is probably still in 4WD after I flip the switch, but why the resistance in reverse? I am sure there is a logical reason, just not in my knowledge base.

nightdrv · **Posted:** Tue Jan 06, 2009 1:35 am

Quote:

is that a lightbar on your KK?

Yea, I just made my own mounts for the lights to bolt on to the Thule roof rack. There is only 3 lights mounted, as the other space is being used by the NV camera. Although, I think I'm going to goto 4 lights, and move the camera and remote searchlight somewhere else when I get my basket and light cage later on.

To_The_Max · **Posted:** Tue Jan 06, 2009 4:57 am

Quote:

I sometimes pull into my sloped front yard if there are a lot of cars in my driveway, i needed 4wd a couple of times to back out to avoid ripping up the grass when we had some snow. KK backs out easily after slipping in 2WD. But as soon as I hit the pavement, the vehicle seems to 'bind' in reverse. Since I am backing into the road, I need to finish a K turn and get out, but the KK seems like it is resisting my reverse motion even after I flip it back into 2WD. Now I know that it is probably still in 4WD after I flip the switch, but why the resistance in reverse? I am sure there is a logical reason, just not in my knowledge base.

If you are still in-the-turn, then the binding is occuring because the front wheels are turning at different speeds and can not relieve the stress since you are on a solid surface now. Because of this binding, it may take a little while for the electronics to "break loose" and go back to 2WD. [At least this is my take on what is occuring but I'm no expert]

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