After putting the 285/75/16s on I've been driving with and without the Power button engaged. It definitely is in a better power band with the Power button engaged and I am getting better gas milage to boot. I know the Power button changes the shift points in the tranny.
Question: Is there any possible way keeping the power button engaged all the time will adversely affect my transmission? The temperature seems to remain the same, even though it is in the 90's here. I also change my tranny fluid and filter every 20K miles, since that's the way I am.

It shouldn't hurt anything. It's mainly there as an economy button, even though it says power.

You might be able to find a chip or other programming device aftermarket that would allow you to operate in economy mode (with the settings as they are in power mode now) and a hotter power mode that will make a bit of difference.

I've noticed that a lot of these import SUVs benefit in the fuel economy department with the addition of larger tires. I think it has something to do with the larger tire diameters helping to get the already high numbered rear end gears back down into highway friendly ranges.

mmmm... i'm surprised you are getting better gas mileage. as i understand it, and as it works on my 1992 trooper, the power button changes the shift points so that the transmission stays in a lower gear longer on the rpm/torque curve.

this should mean that your mileage would suffer. it is not an economy feature at all.

is it possible your mileage shows improvement because you're paying more attention to the way you drive. . .or is it because you haven't taken your new tire size into consideration when calculating your mileage-- i.e. your actual miles are different than what your odometer now shows. larger tires = actual miles greater than indicated.

btw, this affects the speedo, too. and you're actually going faster than it shows.

I am taking the larger tire size into consideration. I always check my gas milage after each fill up. I think keeping the shift points higher helps with the larger and heavier tires, so the efficiency is better than lugging the engine at take off.

All I wanted to ask was if it would hurt the tranny to keep it in Power mode 100% of the time. The ASE Master tech said no, so I'm good. <img src="/forums/images/graemlins/kewl.gif" alt="" />

LEAVING THE PWR BUTTON ON ALL THE TIME WON,T HURT ANYTHING , IT MAY HAVE A SLIGHT EFFECT ON YOUR MILAGE , , MY 2001 WITH 265 70 R16 GET,S CONSISTENTLY BETWEEN 16 AND 17 AROUND TOWN STOP AND GO AND RIGHT AT 19 ON THE HIGHWAY, SW HAS BEEN TURNED ON SINCE NEW AND HAS NEVER BEEN TURNED OFF, ALL IT DOES IS MODIFY THE LINE PRESSURE AND THE UPSHIFT POINT THRU ALL THE GEARS BY KEEPING IT IN ANY ONE GEAR LONGER , HOW LONG IS DEPENDANT ON THE THE THROTTLE PRESSURE , IT MAKES THE TRANS SHIFT A LITTLE FIRMER MEANING LESS SLIP BETWEEN GEARS , HAS LESS OF THE G.M. GRAND MA FEEL TO IT , DEFINATELY LEAVE IT TURNED ON WHEN TOWING AND BY THE WAY THOSE MILAGE FIGURES ARE CORRECTED NO,S JERRY

Thanks Jerry. Appreciate the confirmation from you.

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