power/comfort tranny

[92tank]

i was wondering if i could swap out the trans controler in my 92 with one out a 91 that has the power trans button. or do i need to change the whole tranny

[racing89]

Punched up the wire diagrams just last week for a customer. It appeares that the only diff. is the x-tra terminal in the older controller for the" power" function(recieves 12v. from switch.) Should be doable. The only diff. in the transmission itself for 87-96 is the output shaft in the 87-90 is 21 spline instead of 23

[yuppiexj]

IIRC when the change was made to drop the switch they just put it in POWER mode permanently.
I have a 90 and a 94 XJ
The shift points feel the same when the 90 is in Power mode....comfort lugs the heck out of it.

[92tank]

another qustion is will it help your hurt the fuel mileage?

[yuppiexj]

Not any statistically significant amount.

My 1990 will get the same mileage in power or comfort. +- 1/10th MPG
Comfort lets you lug it a bit more (4th gear with converter locked at 38mph 1100 rpm) but that keeps the engine out its efficiency zone.
Power lets you get up to speed more quickly. then you cruise for a longer period (coast and burn method of driving)

[SilverXJ]

I never actually compared it in my 91 but from what I heard "comfort" actually hurts your mileage.

[Muad'Dib]

Comfort isnt good for the transmission either...

[amcinstaller]

i think the comfort mode also makes the torque converter slip more, and over time would lead to slipping all the time, even when its not supposed to

[racing89]

changes shift points only . wont hurt mileage or longevity. Anyone ever break one?

[92tank]

good to know i guess i will just leave it alone