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power/comfort tranny

Posted: April 11th, 2011, 7:41 am
by 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

Re: power/comfort tranny

Posted: April 11th, 2011, 8:03 am
by 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

Re: power/comfort tranny

Posted: April 11th, 2011, 8:17 am
by 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.

Re: power/comfort tranny

Posted: April 11th, 2011, 9:54 am
by 92tank
another qustion is will it help your hurt the fuel mileage?

Re: power/comfort tranny

Posted: April 11th, 2011, 11:13 am
by 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)

Re: power/comfort tranny

Posted: April 11th, 2011, 5:18 pm
by SilverXJ
I never actually compared it in my 91 but from what I heard "comfort" actually hurts your mileage.

Re: power/comfort tranny

Posted: April 11th, 2011, 10:26 pm
by Muad'Dib
Comfort isnt good for the transmission either...

Re: power/comfort tranny

Posted: April 12th, 2011, 6:20 am
by 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

Re: power/comfort tranny

Posted: April 12th, 2011, 9:05 am
by racing89
changes shift points only . wont hurt mileage or longevity. Anyone ever break one?

Re: power/comfort tranny

Posted: April 12th, 2011, 12:19 pm
by 92tank
good to know i guess i will just leave it alone