Transmission will not go into gear when cold

I have a 1995 Trans Sport with the 3.8 and 4 speed automatic transmission,
it will not go into gear when cold when it warms up the trans works normal
. I have called two shops and all they will tell me is that the transmission needs to be replaced. Is this the case?

Ken

Gm has had a problem with the input clutch seal getting old and shrinking. On a rebuild the seal will be a long lip rubber sealing ring instead of a short lip rubber ring. So if the seal is bad the input clutches wont come on so no forward movement. To get forward you need the input clutches to engage

I'm totally confident troy's reply is factual. Before comitting to a full scale replacement, (specially if after all it functions normally once warmed up,) I'd go for inspection and replacement of the oil strainer in the transmission and fluid replacement , an inexpensive and easily replaceable item that can impair cold oil pumping if clogged. Easing oil pumping might partly counteract and overcome seal leak and allow for quicker engagement. At same time, the amount of clogging might give a clue to the amount of wear of the transmission clutches.
I'm sure you are aware that 4th gear and lock-up function only once engine is warmed up over 140°F.

I will replace the filter and ATF this weekend and see if that helps. I will reply after that.

Thanks,
Ken