no movement forward from stop

[whyte]

2011 ram 3500 6.7L engages 1st gear(audible feelable) then slips out after 10' (loss of forward movement..no sound or jerk)when cold and almost instantly when brake removed warmed up. was stuck in snow. bully dog chip(used for delete) shows p2706 p0731 p0933. 4x4 low drive works in both directions fine (yes i know how to switch out low properly) 4x4high and 2x4 issue occurs, reverse is fine. performed trans fluid/filters change (perhaps some sludge on pan nothing too alarming to this country boy, no filings seeminly good for 120k km). replaced the gov pressure solenoid. checked shift linkage. reset engine and cleared codes. does not allow to start in another gear when selected(normal i believe) however if i get it at appropriate speed for a shift my baby operates normal(managed to make it home until forced to stop help!!!! i know all of what it could be but what IS IT! what tests do you recommend (instructable)


ill buy your coffee at Tim Hortons in the morning