1996 Town and country transmission problem

Hi, everyone. I've got a 1996 town and country LXi, the problem is that
whenever it is put into gear it stalls. It will idle fine in park or in
nuetral but then stalls as soon as it is put into gear. It sat in our
driveway for a couple of weeks before we had the $$ to get it towed to a
shop. when the tow truck driver tried to move it out of the drive it
started and went into gear just fine. At the repair shop the problem
recurred. They told me that the torque converter clutch was locked and
the first thing to try was to replace the solenoid pack as it was also
sticking. I had them replace that and the first time they ran it it went
into gear and was fine but then the problem came back and wont go away
again. It is now at a transmission shop and after taking the pan off
they are telling me I need a new transmission.

I've read about the problems with using an incorrect transmission fluid
and was wondering if this might be the cause and would be an
easier/cheaper fix. We had the transmission rebuilt once already (2
years ago, it was on a warranty then so we didn't have to pay for it so
it wasn't an issue then).

If anyone has any input I'd greatly appreciate it. I'd like to avoid
spending almost $2000 if I can. On the other hand I dont want to keep
trying diffent things and ending up spending several hundred $$ before
getting it rebuilt anyway.

thanks in advance

Dave