I replaced my old tires P235/75R15 with 31x10.50R15. Didn't really notice any difference in auto. trans. shifting at first, but now the trans. shutters and struggles into overdrive. Are there adjustments that need to be made to the trans. and speedometer when changing tire size or is this some other problem unrelated to the tire size? Thanks!

 

I don't think is related to tires My 94 had 265/75/15 and my 95 had 31/10.00/15 . I swapped to the 31's all time and never a had a problem .Its not that big a jump in size. I even had 33's on 1 truck and never touched the trans. Speedo was off . Good luck

 

It is possible to reprogram the speedometer and odometer when changing the circumference of the tires. It is called the PSOM.(programmable speedometer odometer module) I believe that the reprogram procedure is listed on this website in the "Article" section.

The powertrain computer knows what the vehicle speed is from the PSOM.And when changing circumference of the tires--it is possible that the automatic transmission is confused with the new bigger tires.