my buddy's 2001 2500 silverado, 8.1L with Allison tranny dies suddenly randomly. Truck restarts each time, but it's a problem. Tach goes to 0, but lights, etc stay on. Initially, DTC pointed out faulty cam position sensor along with CEL. I fixed that, but now only DTC showing up is a P1779, which is voltage to tranny switch (or something... hard to research)... a bit of a vague DTC actually. It might not even be related. No CEL now, but just that DTC, and a dying truck.

any suggestions or past experiences with this? could be anything... good grief!

Thanks much!

Tristan
'05 2500 6.6D
'86 VW GTI, SCCA ITB car
'04 STi
'06 Atom, on order

 

Ask a tranny shop if they can tell you what it is and how to troubleshoot it. It very well could be a lose wire or even a blown fuse.