I had been experiencing a problem with downshifting into a sort of neutral when stopping and then banging into gear upon acceleration. It's better when cold, as it heats up it gets worse.
I recently flushed out the coolant and it seems to have helped greatly. I still experience the problem, but it takes much longer driving before it starts to act up.
It may also be colder weather, but it seems to me that a warm tranny is a warm tranny regardless of outside temperature after running for a good spell.
Perhaps a new radiator would help, but I need a new transmission...so why bother unless I can really narrow it down to this. The vehicle maintains temperature properly for all engine functions.