AT downshift based on?....

is it a sensed torque load, or a throttle position that causes the kick down/downshift on the AT5? Asking, because of something annoying. Slight hills on the interstate, cruise control, it may downshift and then once on top of the rise, on a flat, it stays in that gear until I turn off the cruise and then re-engage it, or, a slight downhill.

This is not an anomaly, it happens to all automatics I've had in the past. The issue is it's just enough of a need to cause the downshift, and not enough of a need to shift back to the final gear. Of course, I could be asking too much of the vehicle, after all, in Colorado the interstate is 75mph, altitude causes 10-15% power loss depending on temperature, and we all cruise around at 80-82 so the actual aerodynamic loads on top of the power loss could be partially at fault. I could just drive at 75 and have no problems I guess.

 

My 99 does that and it's annoying. Won't upshift till downhill or I shut off the cruise control. My 99 Prerunner never did that.

Check your fluid level, see if it's low.

 

It was on our 01 ford focus, 08 RAV, and now my '11 taco 4.0. I had a mt mazda3 2.3 before the truck and i had relief from the behavior, however I do believe it's the available torque at the given rev range and that car had it and I never felt lacking in any pulling power. Now I'd like to lock out the taco's kick-down because at 2500 rpm I'm cruising at, I know there's enough torque without real lugging, but I think it's the throttle position the more I think about it. So, any real fixing of this would involve adding more available torque through mods, but the downside, going to high flow drop in filters/cai will add filtration issues. (doubling the silica levels of the oil.)

 

My Taco, Ridgeline and Colorado all shifted up once crested the hill.

 

https://www.tacomaworld.com/threads...th-pics-for-second-gen-4-liter-trucks.289913/

 

FYI you can "force" an upshift by moving the shifter from D to 4 back to D quickly if its hanging in 4th up a hill... or did an auto downshift to 4th / 3rd going downhill for extra engine braking that you dont want.