When you place a 2005 model with auto trans in T/H mode?

What changes are made to the transmission: shift points, line pressure, etc:

when in T/H mode, my truck seems to shift much harder or more adrupt

Thanks for any input on this question:

 

The only thing the TH mode does is put a different algorithm in place to run the TV pressure. That said, TV pressure is what influences shift points and shift firmness. The higher the TV pressure the lare the shift point and the more apply pressure is available at the shift point.

 

Thanks for the reply,

but, I need a little more explanation help here.

TV pressure, what is this???

As i understand from your reply, when in T/H mode the shift pressure is higher than in normal shift mode. Is this to insure there will be no slippage of the clutches as the trans shifts gears???

I was told by anothers that the shift pressure does not increase, only the shift points are changed, but that was not my understanding of the T/H mode in the 2005 model.

again, my truck has a much sharper or adrupt shift when in T/H mode than when in normal mode. Something had to be different.

Thanks again for your reply,
Fred

 

TV, or throttle valve, pressure is how the shift points and apply pressures are influenced in the transmission. The mor ethrottle pressure is present the longer it takes gov pressure to overcome for a shift point, and, the higher the TV pressure the more line pressure is routed to apply pressures on the clutches and bands. Thats how shift quality is controlled, you have a soft shift if you are not using a lot of throtttle and a firmer shift if you give it more throttle.

Line pressure never changes but apply pressures do vis the TV valve and that is controlled by throttle position.

The 05+ trucks have a TTVA motor to run the pressure instead of a cable like earlier trucks so now we can have a true TH function instead of just OD off.

 

no 6 no no,

Thanks for the further information.

my 05 model 2x4 has been a great truck so far,

good power and great mpg for a big heavy truck.

Even mama like the ride, maybe because she knows it can pull her travel trailer with no problems.