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When Im' towing 8000# and in Tow/haul command and run up through the gears(auto) sometimes it doesn't want to shift into 5th at times, I will be 2000 rpm's and can run up to 65mph and let off the pedal alittle, and be on flat going and it whats to hold in 4th. It seems like it will want to do it more so after you have been driving awhile. I can pop it out of Tow/haul command and it will shift right away. Anyone else notice anything like this.Its a Job 1 built 4/07 and they did a flash update this past april.
Both my 06 and my 08 would do this. Seems like around 60 mph it cant make up its mind and doesnt want to upshift. Just like you said, hit the button and it will shift. Above 65 my truck does fine.
The reason it does it more after towing a while is the EGT. If you run an aftermarket EGT gauge you will see that when "lugging" the engine at low rpms the EGT's will rise. Once the tranny down shifts and raises the rpm's the EGT's go back down. So the computer is telling the tranny to downshift (or not to upshift) partly because of your speed and rpms, but also because of the EGT's.
Isn't this what tow/haul if for...doesn't the computer do what is best for the engine? I used to do the same thing by switching out of tow/haul until another truck buddy told me that it is far better for the engines to have higher rpms under load (9000lbs camper) than lower. Thoughts?
driving on the flat doesn't make much difference, if the motor is lugging at lower rpms then the egts will shoot up fast, higher revs in that situation bring them up at a slower pace
Isn't this what tow/haul if for...doesn't the computer do what is best for the engine? I used to do the same thing by switching out of tow/haul until another truck buddy told me that it is far better for the engines to have higher rpms under load (9000lbs camper) than lower. Thoughts?
If im on any kind of grade I let it do what it needs to do. I will switch it out early if its flat. Good argument tho.
bout sums it up. There are stretches out here that are just even grade for miles. Then you have to go over the mountain passes. Every time I do, it makes me smile and glad I bought this truck..lol.
The EGT suggestion sounds reasonable.
I don't have that issue on my 05 V10 with the TS. It settles right down to 1800 at about 60 towing 9k enclosed car trailer.