Hey All,
I got a 2008 F750 with the Cummins, Allison 6speed powertrain combination.
The Allison shift panel comes up with a trouble code something about torque convert er lockup selenoid circuit low, They say it may be a wire broken or chafing wire somewhere. The Allison people want to replace the computer and valve body on the transmission which will break the bank!

The tranny has not engine breaking and the torque converter does not lock up and the Jake brake does not work.

Has any one run into this problem, what was the cure?

Thanks for replies,
Bubu 11

 

could be internal harness or external harness could be solenoid very rarely do i ever replace tcm or valvebody need tranny model and code to do more research

 

Long and short of it, the wireing harness was rubbing against the transmission, 3 wires shorted out. Dealer lengthened the wires and repaired the harness. Shifts good now!

I was charged 250.00.

 

Sometimes its well worth it!

 

external harness was my first guess in the 10 years i have been working on allisons i have never replaced a whole valvebody and only a few tcm s with a solenoid code