2014 Taco 4X4, DCSB, will a tire diameter increase change transmission shifting?

My last Toy was a '07 FJ with manual trans, which was my last Toy to modify. But after many years of manual transmissions and being able to modify to my hearts content (mostly Fords and Toyotas), I now own a '14 Taco with an automatic trans (something new to me) I'm considering going to a taller tire. I have searched for hours to find out if there were any owners who've experienced any automatic shifting issues when changing out tires from 265/70/16 to 265/75/16. I've never owned a vehicle with an automatic, let alone a computer controlled auto-trans. The shop foreman at my dealership (a good friend) insists that going to a taller tire will adversely impact the shifting operation of the transmission.

I'm hoping owners who have done this, with out lifting or moding the suspension, can let me know if they've experienced any adverse shifting of their auto-trans.

 

No you will not have any issues at all.

 

Shifts just fine. It will throw off your speedometer a little though.

 

Didn't throw mine off at all.

 

Just put 235/85/r16 on my '14 DCSB auto. They are just a smidge taller than 265/75r16s and there are no problems with shifting even though I drive steep roads at high altitude and haul a light trailer. Bonus, my speedo is closer to true speed than it was on the oem size tire.

 

Things have changed a little since '07....I owned a '05 Taco and a '07 FJ, both had 6 speeds manuals and from the day I bought them, the speed opmeter was always overly optimistic. Changed out their tires to a full size taller and they were fine from then on and I found out what the real MPG was.

Not the same with my '14 Taco, the speedo is spot on all the time. I noticed Unchained has no issues, appears he now has the same tire ratio that I'm planning on making.

Hope I hear others responses with '14 or '15s too, that confirm.

 

What was your computer saying??

MY 07 speedometer reads 2mph slow (with stock tires). I checked it against a GPS. However with a scangauge hooked up to the ECU, the computer is reading completely accurate with the GPS. So - the calibration of the speedometer isn't accurate to the numbers on the dash. What you see on the speedometer isn't exactly to what the ECU is getting.

With taller tires - it will change how the computer gets information regardless of what the speedometer reads. Your odometer should be checked against (say for instance) highway 1 mile markers to compare to your odometer.
Your speed...well...check against a GPS.

 

Wanted to express my appreciation to everyone that gave me feedback.

I was able to the get the wheels I wanted and had them powdercoated last week. Then I went to my favorite tire supplier and had them install the BFG AT, 265/75/16....I had my mind set on NITTO's, but one look at those BFG's and I couldn't resist....very surprised that they're not noisey...but they sure handle nice.

I'm happy to say that not only does everything look titsup, but the speedo didn't flinch and absolutely no issues with the AT shifting erratically. Had my friend at the Toy dealer take it out for a spin and he was surprised it turned out so well. Thought I'd post a couple of pics:

 

Great choice on the tires, I got the same ones a couple weeks ago and I love them so far.

 

I've got the ko2s myself in 265/75/16 and due to the change in diameter and weight from a stock tire, I've noticed my truck downshifting on grades it never used to with cruise control engaged. Not that noticeable with cruise off though.

 

I haven't noticed any change like that....what tire pressure are you running on the BFG's? Anything over 32 to 34 PSI might cause what your describing.

 

I went to a 265/75 r17 Duratracs on my 1st generation and I found the truck was always searching for the right gear especially in cruise control...was a big fan. I really want to go with a 265/70 r17 on my 12' but I am afraid of the same thing. But if I do decide to do it would be a highway tire like a Michelin M/S 2 and not to a All Terrian.