Caravan transmission problem

I have a 2000 grand caravan that has no reverse. When the problem started, it had no forward or reverse and a low ticking sound in reverse. Had it towed to the house where it sat for months. Decided to remove and charge battery and start engine. To my surprise, when i started the van and shifted into drive, the van moved forward and trans would hold even when brake applied without slipping. When i shifted into reverse, i had nothing but a low ticking or knocking noise. Does this sound familiar. Could it be an axle problem or a definite transmission failure.

Check the transmission fluid and level first, how long since a trans and filter change?

About 10000 miles since filter change. Fluid level ok. When problem first happened engine temp went very high at idle but does not happen now

When the auto transmission on my 70’s Ford truck started going out, this was the symptom.

What’s the mileage?