Last year I had a scary situation with my factory opened 6 spd bus, it felt like the TCM was resetting itself causing a "jolt/kick" when switching gears. Only did it from a stop or a slow down, downshift then upshifting.
My issue turned out to be that the blade fuse holder in the battery box, one leg was overheating. You could visibly see one leg was darker than the other.
I cut out the fuse holder and replaced it with a new one, fuse too, problem solved.
Post #17 of
this thread and you can see a pic of what my fuse holder looked like.
quick advice, Check your fuse holder....