1988 Ford Aerostar

I have a 88 Aerostar van with a 3.0L V6 and an A4LO automatic transmission with overdrive. The transmission is out on my van. I was told that on this year van the transmission was too small and that it needed a bigger one. I was wanting to know if there is a bigger transmission out there or if I can use a transmission from a different vehicle. Any help would ber helpful.

I have a pair of Aerostar vans, a 1990 4.0L and a 1991 3.0L. Both of these vans were purchased used with over 70K miles each. The transmissions are both A4LD's and RWD. I had to have the trans for the 91 3.0L rebuilt recently. I have been told by several reputable rebuilders that the best fix for the A4LD as used in the 3.0L and smaller engined vehicles is to rebuild it using parts for the 4.0L version, or to get a good 4.0L A4LD and swap the bellhousings so it will bolt up to your 3.0L.
I've been shown the physical differences in the internal parts between the 4.0L version and the lighter duty A4LD's and believe that it's the only way to go. I've used my 4.0L Aerostar to tow a 3500 lb. race car and trailer combo for going on ten years and have never had any problems with the transmission in it.