The transmission control modules on the General Motors 2009-15 Duramax trucks are well known for causing issues.

Symptoms include setting codes, rough (or no) shifting. The problems begin intermittently, and continue to get worse.

If caught early enough, we are able to repair them.

What happens, is that super-fine filaments are used to connect the exterior pins to the circuit board inside. There is a flaw in how these are soldered to the contacts, and this flaw causes the filaments to break off of the connector pads at the connection pins.

The repair involves removing the conformal coating, then re-soldering all filaments to the pads. Once done, the filaments are individually tested for 0 resistance, and then the unit is coated and re-sealed.

These filaments can also completely break off of the pads, and short against each other. Once this happens, the TCM is almost certainly not repairable.