2.7 autosmatic and larger tires (overdrive)

Please move this if it needs to be in the tire section but I'm looking for bigger tires (maybe up to 31 by 10.5) for my auto but my question pertains to just being in overdrive on the highway (for those that have experience with the auto). I've read so many posts but most have the manual and wouldn't apply. My truck has the stock 225/75/15 tires and wondering if I'll essentially lose overdrive if I go to the larger size (not opposed to even doing 30 by 9.5 either though. I have 4.10 gears (not regearing) but if the slightest incline will kick me out then I might pass. With overdrive now I can climb a lot without it kicking off.

 

i have 32 on my 2007 2.7 auto with stock gears and it does ok on the free way still get around 31 mpg but also have afe cold air intake with DT hearder, so you should be fine if you have 4.10 grears i would go with 32 s. you should be fine bro

 

thanks for the reply. yeah i've got an aftermarket muffler/high flow cat/k&n filter, it came on it don't flame me please. And a ported 01-04 mini header with the elbow mod done so it's got more pep than stock. I'll be getting the 31 by 10.5 for sure then.