2001 Allison 1000 5 speed. Completely rebuilt transmission high performance clutches triple dish torque converter. So got the transmission put back in the truck got it back on the road drove for about two weeks and the truck went into limp mode and now has no forward gears. Pulled transmission out checked all the clutches no burnt clutch is everything looks good in there.. still no forward gears. New safety neutral switch, new ignition switch. Oh and The D is flashing Also Please help I’m at a lost!!!