Transmission question.

[TokenMinivan]

First post... somewhat redundant question!

We bought a 1995 3.0L Aerostar, nice van for the money... until today when it decided to take a nap on my wife.
She said it began shuddering and then acted like the transmission was slipping. Now that I've had a chance to get it home and check it out... it's a little odd. (Mind that the last Ford I had was a 1984 Escort GT... it was bad enough that I swore off Fords FOREVER... until now.. actually, the van seems very well made, enough so that I'm giving Ford another chance.)
It acts like the pressure in the tranny (A4LD, but you guys know that already) is way low. It will move in drive and reverse, but you have to rev it to about 3000 rpm before it starts to move, below that and it's like it's in neutral.
I searched the site and found a few references to similar problems and now I'm guessing that either the pump seals or.. (gah, I went blank!) another set of seals went south.
There is some leakage between the motor and tranny, but I don't know which it's from. The fluid looks good and is at the right level.
So, before I tear into this thing, what should I look for and where is a good place to order the parts for it? As long as it's out, is replacing the pump a must if it's not damaged? The van has about 120K on it.
For the record, I've rebuilt engines, manual trannys, t-cases, diffs, etc..., but never an automatic, so this is uncharted territory for me!

 

[BrooklynBay]

Welcome to this forum! Start with the valve body. Add Sonnax upgrades like the end plugs with O rings, boost valve with O rings, and new valve body gaskets. The sticky thread in the transmission section called the A4LD valve body rebuild diary explains how to do these things.