1991dodgegrandcaravan transmission problem

I have a1991 dodge grand caravan , I have it 3 years .It seems every time the summer comes around my transmission acts up. For instance, if I go more than say 20 miles and the tempeture is say 87 it sticks in first gear, by the time i make it home after stopping to let it cool down it will idle but not go in reverse until the engine has sat cold for about an hour then it is like nothing ever happened , good as new . But when the winter comes around it's like nothing was wrong it drives great. now here it is summer again and I can't go more than 10-20 miles and it sticks in first gear. If anyone could offer some suggestion it would help a lot. Or if someone else has ever run across this problem.

What engine do you have in your Caravan ?

I'm not quite familiar with transmissions, but based on personal experience, I would say your transmission requires immediate attention.

My dad used to own a 1984 Reliant S/W, 2.6L. The symptoms you've described is very similiar to what happened to his car. Only thing is, we had the transmission fixed before winter. His car did the same thing, when cold, the vehicle would shift from 1st, 2nd, then 3rd. But when the engine temp got hot, the vehicle would never shift into 3rd. Reverse was still ok regardless of whether the engine got hot or not.

We finally took it into a transmission shop and the vehicle required a totally brand new (or rebuilt) transmission - $1500.00 CDN incl. labour.