Tranny leak

Main suspect is a front pump seal is leaking. Fluid will run out from the bottom of the bell housing right behind the engine.

Actually that shouldn't do it, but with no fluid circulation, rubber seals can dry out. There are seal conditioner additives in oils to keep them pliable, so running the engine even once every few months should be sufficient to keep them wet. I've seen front pump seals suddenly crack from dry-rot and start leaking on vehicles that are being driven daily. What is more concerning to me is the fiber clutch plates drying out when the fluid runs out of the rotating housings. We soak those plates in transmission fluid before installing them during a transmission rebuild. That is so they aren't dry when the transmission first starts spinning. It seems to reason the same damage will occur to them on a vehicle that sits for a long time. That said, I have a '93 Dodge Dynasty with 4,950 miles. It has sat multiple times for more than six years without being started. Drove it well over 100 miles this summer, ... And no transmission problems.

The time when front pump seals are most likely to leak is after a removed engine or transmission is reinstalled. That seal gets hard and brittle from age, then when the engine and transmission are separated, the full weight of the torque converter drops down on the seal and cracks it. Experienced mechanics will try to stuff a wedge under it to support it, but that rarely works. It's best to just include a new seal in any repair procedure. Once the parts are separated, it just takes a couple of extra minutes to pop it in.

I'm sure sitting has had something to do with this, but blame it more on mileage.