68RFE-07.5/6.7Shifting PROGRAM

[ejlbuild]

I asked this question right after i bought the truck in 07. When going down hill in Towhaul, if I slow the truck down to 29 mph the trans drops out of gear and the rpm drops to 750 if I let the speed come back up to 30 the trans will reingage. This is when the truck is empty or loaded. It is computer program problem and when I asked the service dept. at the dealer they know nothing. Does anybody know of a reprogram or possible dealer flash.

Thanks Eric

Portola Valley,ca.

 

[Hoefler]

Do you have the exhaust brake on?? If not, turn it on. I have never experienced it dropping out of gear before about 10 mph and in 1st gear. Towing or empty.

 

[DanSullivan]

I also have never had a problem, you did not say you had the exhaust brake on. Mine slows down very fast in tow haul and down shifts quickly especially when you step on the brake pedal .

 

[Cosmo]

You sure it's dropping out of gear? Sounds like it's just unlocking the converter, probably staying in 4th gear.

 

[cerberusiam]

That sounds like it is just unlocking the TC and going into freewheel at that point. If you use the EB does it downshift and slow further while engaged?

 

[Alan Reagan]

Mine unlocks the TC at 35 mph usually with the EB on and in Tow/Haul. If I am in stop and go, it will hold it a little longer but usually no lower than 30.

 

[Newt]

If you guys will watch your tach, I think you'll find the EB is more RPM rated then MPH. The lower your gear the slower it'll be engaged.

Newt

 

[Alan Reagan]

The TC appears to unlock at about 1500 rpms without tow/haul and 1100 with tow/haul. I assume it is probably in third or fourth gear when it unlocks.



In tow/haul with the EB on, going downhill, the engine will start downshifting if speed is increasing. That's when you really feel how much it is working.