[rwhite65]

everyone on here has said some really good ideas, but look to the simple ones first.
Obviously like was just mentioned, check the fluid level. After that, I think the thing being cold could be part of the problem. Mine sits sometimes for 8 months of the year. I always start it and let it warm up, but the tranny fluid does not really start to warm up til u drive it. After mine has sit for that long, it takes it forever to shift but finally will. After that, it should start to shift more normal. It should only do this when it has sit for a long period of time (a month or more). After checking these few simple things, then the other things might come into play if u still have shifting probs. It took me a long time to realize, it was something stupid and trivial, cause I was always thinking the worse (big money items).
good luck
Ryan