OK, I searched, but didn't really find anything useful.

I have a '98 Windstar with only 54K miles that has the all-too-common problem where it will slam shift from first to second under light to no throttle conditions, and it will also sometimes slam from third into second when slowing down, to go around a corner for example, and then lightly pressing throttle. I had the downshift slam problem addressed a couple years ago while still under warranty, and it made it about 95% better, but didn't completely solve the problem.

I'm trying to sell this thing and an ex-inlaw wants it but says a tranny shop told him "Oh yeah, I know just what the problem is and it's $1100 to fix it". This same shop also said changing the tranny fluid a few hundred miles ago was "the worst thing I could have done". B.S. This is the actually the third time the fluid has been changed. Besides, I think the idea of not changing tranny fluid makes about as much sense as not changing the oil in the engine if you forget the little sticker in the window and accidentally going over 3000 miles. Needless to say I won't take it there to get any work done and I don't want to drop my price that much for an otherwise spotless vehicle. I know there are tons of TSB's about these issues. Has anyone here had these problems fixed on their Windstar? I need some kind of an idea what the "real" cost is going to be to get this thing fixed.

 

I recently had the same problem and went through the same motions as you did as far as the fluid changes and it turn out to be my TPS (Transmission position sensor) I was out $100 half was labor, I could've done it myself but I just knew I was screwed($1700 new tranny) So with all that said give it a try it's only $50
Try this web site:
http://www.cartrackers.com/Forums/live/fordwindstar/
You will have a little more luck at this web site these guys are really helpful.