It is absolutely frustrating to need a transmission.....$$$$
I went through that with my '96.
I did a LOT of reading and am very happy that I did.....and avoided getting a cheapie unit localy for 1/2 the cost......as many folks had problems with those.
I bit the bullet and got mine through FORD, which in 2000.....the one for my '96 would get whatever updates were appropriate.
I had been having the dealership do fluid/filter changes at 30K miles.
I also installed a auxillary transmission fluid cooler (I tow a utility trailer once a year) and went to yearly fluid changes......started off with Mobil 1 , then I switched over to Redline D4..... Either fluid is great.
The replacement transmission had over 140K miles on it when I sold the van (over 220K miles on the vehicle).