This is a line that is listed in a 04 CTD TSB that applies to my truck. The TSB is a ECM flash that fixes a few problems, but listed this line as something else it will do. What exactly does this mean or do to the drivability.
"The new engine controller software also includes a change that allows automatic transmission equipped vehicles to lock the torque converter clutch when a manual 2nd gear downshift is selected."

Thanks for the clarification..
DD

 

does exactly what it says. normaly the 48RE only locks the TC up in 3rd and OD. the new software will lock it up in 2nd to help with towing and breaking when used with an exhaust brake.

 

Forgive my ignorance, I'm still learning and not as experienced as my use of acronyms may have indicated... When a TC locks up, does it mean it won't allow for the trani to shift, holding it in the specific gear.
Thanks
DD

 

Lock up means your lock to the engine, so if you got pac brake it will help you slow down with engine braking andnot free wheel