My stock tires were 255/70/16. I replaced with 265/75/16. The shift between 1-2 is very sluggish. I have a tuner and was wondering if I played with the option for changing rear gear ratio if this may "fool" the computer and make it shift different. Or just wasting my time? Currently have 3.55.

 

What type of tuner do you have? You need to change the tire size, ie the dia in millimeters or the rev per mile number to fix your problem. the circumference of your old tire was 2399mm and your new tire is 2525mm. The revs on old tire is 671.038 and the new tire is 637.231. Set it to the nearest in increments of 5 i think. So set it to say 640.

 

I have the hypertech power prog III. It sets using inches. Stock is app 30 and new is 31.6 inches of travel/rev.