I'm watching this one more closely... I have a 2000 Caravan that I just picked up and fixed (water pump...)
Mine has a 2.4 liter, 31TE (A413) transmission, no OD, 3 speed, not electronically controlled, but it has lockup, which is great.
I'm currently running 0w30 Mobil1 oil in it, and a SRT4 oil filter (nearly 2x bigger than the OEM unit.)
There is some great information on tranny mods at
Donovan's Dodge Garage.
The site is mostly geared toward racing, but most of the Auto tranny mods and information will help out alot in making the auto tranny more efficient.