Need help

[nick97]

I have a 2008 3500 savana with a 6.6 ltr duramax diesel the check engine light came on with the tcc code and the tcm code ,I replaced them both and still my trucks check engine light is on, the truck is shifting hard into gears 1-2-3 and doesnt shift down a times to slow down!It is off and on ,and it feels like the engine is low on power ,then it gets it then cuts out kinda thing?Ayone have any ideas here Im at a loss??

 

[Molson02536]

I have a 2008 3500 savana with a 6.6 ltr duramax diesel the check engine light came on with the tcc code and the tcm code ,I replaced them both and still my trucks check engine light is on, the truck is shifting hard into gears 1-2-3 and doesnt shift down a times to slow down!It is off and on ,and it feels like the engine is low on power ,then it gets it then cuts out kinda thing?Ayone have any ideas here Im at a loss??

Start with the simple and since you covered the TCM by replacing it, inspect the wire harness for breaks and that the pins at the connecting joint are not corroded.

Hard shifts could be from a bad TPS connection or readings and no down shift could be from a bad VSS connection also.

Good luck and keep us posted.
Molson02536