Hello guy's. I have a M936A1 . My transmission is now slipping when shifting between first and second gear. Also when it downshifts from second to first it drops in extremely hard. I have done my fair share of reading and can't really find a answer for the question I'm about to ask. Later on I am planning on going with a big cam Cummins 350 or 400 when mine if ever fails and have thought of upgrading my Allison tranny now . My question is what will be the most logical upgraded transmission to use ? A HT740D? I'm just not sure of my options so any and all opinions will be helpful.