Complex sentence: Packard was caught in a bad competitive spot, becasue Cadillac, their main competitor, had self-shifting Hydramatic Drive from 1941, and was selling ever increasing numbers of automatics on their cars for 1946-1948.
Split into simpler sentences: Packard was caught in a bad competitive spot at this time, becasue Cadillac; their main competitor, had self-shifting Hydramatic Drive from 1941. This cuased Cadillac to sell ever increasing numbers of automatics on their cars for 1946-1948.