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89 xj tranny switch ?

N

nuttinbuttmudd

NAXJA Forum User
Location
Alaska
ok got a 89 xj with a aw4 tranny

got a switch on my dash looks simular to this


trans
power
_____
[ switch]
______
comfort

crude looking switch but example

what does this do and where is it located on the tranny?
has not worked for the life of the jeep with me,

hit switch light comes on but nuttin seems to happen
 
nuttinbuttmudd said:
ok got a 89 xj with a aw4 tranny

got a switch on my dash looks simular to this


trans
power
_____
[ switch]
______
comfort

crude looking switch but example

what does this do and where is it located on the tranny?
has not worked for the life of the jeep with me,

hit switch light comes on but nuttin seems to happen
Click to expand...

'Never had any problem with mine but I can tell you what I think it does.

Power = let's it downshift with less throttle position and changes the torque convertor lock-up curve. Shift points are also firm compared to comfort setting based on similar load, speed, throttle, etc. Just a guess but mine seems to get roughly 1-2 mpg less running power mode.

Comfort mode is basically the reverse of the Power modes. Shifts aren't as hard, it takes more throttle to downshift, torque convertor seems to lock-up sooner and stay that way under similar load/driving conditions.

There's a couple wire runs to the tranny. Just follow the ones that aren't part of the NSS and qualify their connections.

It's a subtle thing but there is a difference between power/comfort modes.
 
89 or 90 was the last year they used that switch. The difference is subtle -- yours may work and you just don't feel the difference.

The newer XJs are hard-wired to the "Power" position, because it's not as tough on the tranny. I recommend that you put the switch in that position and forget it.
 
Hell thats what it dose .When I turn my switch on the the tranny stays in LOW gear and will not shift.How can I fix that?

PS.Not trying to steal your post.But ti's the first time I've seen a post on this problem.
 
nuttinbuttmudd said:
any way to tell if it is working i could never tell from either position
Click to expand...

The way I could always tell was drive up a hill, with it on comfort, that the tranny shifts to 3rd in and seems like it shouldnt quite be there yet and then switch it to power with the same amount of throttle applied. It should downshift if it is working. I know those were some pretty crappy instructions but I hope it helps.
 
vcbuzz said:
Hell thats what it dose .When I turn my switch on the the tranny stays in LOW gear and will not shift.How can I fix that?

PS.Not trying to steal your post.But ti's the first time I've seen a post on this problem.
Click to expand...


np that is why i asked lol

i dont think mine is working

wonder if there is supin i can replace to make it work ?
 
Hopefully this will explain it for you. Traveling at 45 MPH (for example) in power setting, you stomp the accelerator to pass some one. The shift will be very firm and quick. On the other hand in comfort it will or should be noticeably smoother. Like Eagle said, if it turnsout to only work in "power" your better off. What most people dont realize is that the "smoother" a shift is with an auto. the more slipping is happening which creates heat and wear.
 
So if I have this right our 'new' 89 should be run all the time in the power position around town ? and comfort on the hiway ?
 
RichP said:
So if I have this right our 'new' 89 should be run all the time in the power position around town ? and comfort on the hiway ?
Click to expand...

I leave mine on power all the time. Going down Rt. 30 theres all those hills so it makes it downshift a lot quicker so I can maintain "the speed limit". It goes into OD either way after you hit like 60.
 
jeeppowermj said:
I leave mine on power all the time. Going down Rt. 30 theres all those hills so it makes it downshift a lot quicker so I can maintain "the speed limit". It goes into OD either way after you hit like 60.
Click to expand...

Cool, that works... so what is the advantage of the 'comfort' setting, has to have something or they would not have wasted the money on it...
 
The switch is wired to the trans computer (TCM)... there are two sets of programming in the TCM.. the switch determines which programming is used.

It changes shift points and line pressure according to throttle position and vehicle speed.

If you don't think it is working, try this: put it on comfort and drive it at a speed/load where the engine seems to be lugging and needs to shift down.... instead of more throttle, switch to power mode.. the trans will shift down without more throttle applied. You should also notice earlier/firmer downshifts when slowing to a stop, and later/firmer shifts when accellerating.
 
I've only "eyeballed" the odometer at the fuel pump for this but I'm 99% certain POWER uses more fuel than COMFORT. Because of mpg, I primarily use COMFORT mode and at +260k unopened miles I seriously doubt it has caused any excess wear. In fact, I don't think the tranny "slips" more in COMFORT mode but it shifts at different points and the TC lock-up happens differently.
 
Its not that the tranny slips as an old wornout one would. What I ment by "slip" it that the engagement between gears is longer,not as sharp. During this time the rotating parts are "slipping" more than they would in power mode. It really isnt even something you can feel. I have a friend who has owned two modified Ford Super Duty PowerStroke trucks and this is the problem that they are beginning to runinto now that they made the shift points softer. The increased power makes for increased heat because of the "slipping" involved in softer shifts.
 
I've run mine on power for about 6 months now and I have noticed very little of a drop on gas mileage. I figure if it makes the tranny last that much longer I'm better off with that than saving a dollar at the pump.
 
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