what are the extra gears for?

[jesse_sarver]

hello, I have a 2000 jeep cherokee automatic transmission. It has an extra 3rd and 12th gear. What are those for?

[AlohaBra]

It is there in case you want to down shift manually.

The lower gears are 3rd, 2nd and 1st (2-1 is combined, not the 12th gear that you indicated). Try down shifting it when descending steep hills or climbing steep hills and you will see its purpose.

[jesse_sarver]

thank you, I know it might of been a dumb question but now I know! I don't know that much about vehicles. I thought one might be an overdrive gear. I'm looking for some way to get better gas mileage out of my jeep. I just got a new job and its a hundred mile drive round trip everyday and I don't want to get rid of my Jeep. Thanks for the info.

[sector95]

Hey Jesse...

Welcome. The automatic in your cherokee is a 4 speed overdrive transmission with a lock-up torque converter. It is called the AW-4 (for Aisin/Warner ...yes it is a Japanese made tranny with variations found in some Toyota SUV's).

On the shift quadrant you have the ability to select:

D, 3 and 2/1

D: the normal position for most driving; it gives you three gears plus overdrive and torque converter lockup. You will feel three shifts: 1/2; 2/3 and 3/4(overdrive). At about 42mph you will feel a fourth "shift" which will be the torque converter locking up (you can watch the tach drop quite a bit as the converter locks up). What lock-up means is the engine is mechanically linked to the tranny instead of through a fluid-type of coupling; this gives better gas mileage and quieter cruising.

3: the position used for towing or for hilly terrain to keep the transmission from shifting in and out of overdrive and converter lockup. The tranny will shift twice 1/2 and 2/3. You get more power in 3rd for towing at the expense of mileage. Downshifting from Overdrive into 3rd gives a *little* bit of engine braking.

1/2: this is the funky part of this tranny and one that a lot of guys shake their heads at (me included). If you are cruising along and downshift into the 1/2 position, depending on your speed, the tranny will downshift to second gear and hold second gear until your speed drops to about 25mph at which time it will dump itself, with great fanfare, into 1st gear and stay there (even if you accelerate above 25mph). If you start out in 1/2, the tranny will stay in first gear. There is no easy way to select and keep second gear in this transmission.

Hopefully this hasn't confused you too much. Overall, this is a pretty reliable tranny and for 99% of the time put the thing in "D" and go for it.


Mike
00XJ

[dave92cherokee]

That's not totally true about the 1/2 selection. If you're like most of us you want more control and as such mod your jeep. Check out this sight it shows how to wire up two switches to manually select 1st or 2nd gear and keep it from shifting back and fourth.

http://www.go.jeep-xj.info/HowtoAutoSwitch.htm

[sector95]

Originally Posted by dave92cherokee

That's not totally true about the 1/2 selection. If you're like most of us you want more control and as such mod your jeep. Check out this sight it shows how to wire up two switches to manually select 1st or 2nd gear and keep it from shifting back and fourth.

http://www.go.jeep-xj.info/HowtoAutoSwitch.htm

Well that looks like a neat setup, especially the "tip-tronic" circuit board. I've seen some of these homemade "black boxes" and they always looked, well, homemade. I marked the site and will look at it again, including the link to the guy doing the circuit board. I have (and the original poster has) a 2000 Cherokee so we would be faced with the CEL coming on for (according to the site) 50 on/off ignition cycles. Of all the installatins on these kits I've never seen one done or documented on a later model XJ ('97 and up); I'd be suspicious at doing potential damage to the TCU by wiring one of these into the system. I've got one of those code reader/clear code devices so it would be a minor inconvenience for me but the original poster was not a "gear head" kinda person.

Thanks for the link....

Mike
00XJ