shifting issues

Took my TRD Pro across TX to New Mexico. The speed limit in West TX is 80 mph so I set the cruise control and noticed something odd. While going up those huge hills the truck would downshift to maintain speed, and rpm's jumped up to 3200. At the top of the hills when it leveled off, my truck would stay at 3200 rpm's. It would only downshift if I was on a decline or if I took cruise off. It shouldn't do that right? Any ideas? I thought about taking it to the dealer and have it checked out.

 

Not good to use cruise control on these types of roads. I'm pretty sure it says this in the manual. All of them I have used have a tendency to do this.

■Situations unsuitable for cruise control
Do not use cruise control in any of the following situations.
Doing so may result in loss of control and could cause an accident resulting
in death or serious injury.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as those covered with rain, ice or snow
●On steep hills
Vehicle speed may exceed the set speed when driving down a steep hill.
●When your vehicle is towing a trailer or during emergency towing

 

I live in the country with small, rolling hills and have noticed the same thing. I can reach the peak of a small hill and the motor will still rev at high rpm's and I'll have to accelerate in order for it to shift.

 

That is standard for these trucks. There has to be enough reserve power for the computer to shift the truck back into OD and at 80 MPH you are taxing the reserve. That is why you have to let off the gas which makes the computer think the reserve is met.

Think of it this way. On a scale of 0 to 100, and your speedometer being that scale rating your available power, at 80 MPH you are using 80% of the vehicle's available power. That only leaves 20% and that is not enough to cause the truck to shift back into OD. Slow down to 60 or maybe 65 and the truck will shift back into OD at the top of the hill.

If you had a bigger engine or a SC the truck would shift back at the top of the hill or before when running 80, but for now at those speeds you are taxing the engine above what the computer will allow an upshift into OD.