Tacoma drops to low RPM (1k) when going downhill at highway speeds

Hi all. As the title says, when I crest a big hill, my truck's RPM's drop down to 1k, at 70+mph. If I tap the gas pedal, they bounce up to 2k and back "into gear". If I don't touch the gas and just coast down the hill, it stays at low RPM.

I'm sure that Toyota does this to maximize MPG, but I watch the torque converter temp increase quickly when the truck is at 1k. After a long hill climb I can be pushing 180F and then it will creep up to 200F if don't tap the gas.

It seems like the truck drops into neutral, and then when I tap the gas, shifts back into 6th. Like I said, this happens even at 80mph. Anyone else notice this?

 

The transmission does drop down a gear to help with slowing down. It helps save your brakes. It's normal.

 

I'm pretty sure that the engine down shifting for engine braking purposes would cause the RPMs to increase, not decrease.

 

The torque converter unlocks when the gas pedal released, putting the converter into a partial slipping mode. Therefore you see the increase in the temps.
I suggest to get Fusion Obd2 or other phone based apps and look at a whole picture. The tranny does not drop to neutral. If you are not tuned, it stays in 6th. The minimal downshift speed (zero accelerator) on OEM calibration is very low.

 

Learn how to use 'S' mode; you can then modulate RPM'S directly.

 

A third-generation Tacoma only running at 1000 RPMs at 70 mph is likely due to a significant transmission issue, most commonly a slipping clutch or a faulty torque converter, causing the transmission to not effectively transfer power from the engine to the wheels, resulting in low RPMs at high speeds.

 

This tranny has 3 phase converter. It is normal

 

I can’t disagree you definitely know more about these trucks than myself.

 

It does exactly what you explained -slipping while stuck in 6th (0.58 ratio) and downshift speed at 0 accel somewhere around 30 mph.

 

Yes, I noticed the same with my wife's Tacoma. This is a normal function of the Tacoma's transmission. I find it useful sometimes when exiting the highway and moving slightly downhill to the stop light. Just when I release the gas pedal to coast to the light, it feels like engine braking.

What surprised me a lot was when driving at 35 MPH with the radar (cruise control) turned on and all of the sudden the truck applied the brakes to slow the speed down. I had forgotten that the cruise control was turned on while I was following a truck. The truck made a fast right turn without blinker or warning into a parking lot, and by the time I was applying the brake, the Tacoma beat me to it. I just looked at my wife and said, what the heck was that? She started laughing and pointed at the cruise control being active