I would start with checking all the fuses, that is why they are there, to burn out before a part.
What is another name for the vandura? The model number?
For a 5.7L engines with automatic transmission, click here.
It appears to be under the drivers seat.
You might also want to check the alternator output, cause when the battery shorted out it could have blown up a diode or two inside the alternator. Did you also check the fuse for the transmission?
That is either the 1994-95 G-series gasoline engines with 4L60E transmission
or 4L80E transmission.
I meant to check the alternator output in order to determine if that may have been a problem after the battery shorted out. Just replacing the alternator doesn't insure that the wiring to and from the alternator is still good.
The owners manual should tell you which fuse is for the transmission.