1995 With shift problem when cold.

I've got a 1995 Windstar with a weird problem. Only happens when cold, like below 30. Only happens once, then goes away. After starting, shift into drive, shifts into 1st fine, then gets to about 2500rpm, feels like it wants to shift into second, might actually, but stays in first for about a mile (or I do the shift into 1st then up through the gear thing), after it shifts into second no other problems, even after stopping (okay, an occasional hard shift into second, not crazy hard), but works fine after that. Had the tranny fluid/filter thing done and of course after driving it to the shop won't do it again for the mechanic. Any ideas, hints?

let your van warm up for 2-3 mins in very cold weather. -30
If start your van and zoom of. Your fluid isnt warm enough to do its work
. try warming it up before you leave. Its always good to warm up any veichle any temp!. Check your tran fluid height after you have drivin for a few minuites- put the car in park(running)(warm) check level 2-3 times
check color, smell.

Thanks for the response, but thats another part of the wierd, I can let it warm up for as long as I want (once for over 30 minutes) and it still does it. I've checked the levels, even after just having the fluid/filter changed. Thinking it's got to be a sensor/electronic issue, but not sure where to go from here.

how high does it rev before it shifts into secound.?
Does it shift hard?

If I "push" it, it shifts about 4000, or I usually just let it "warm up" at about 15 mph and about 2500-3000 rpm. When I use the lower rpm's it slips in after about a mile, and not hard. But if I rev it up and force it it does shift hard. hope this helps....