Anyone knowledgeable on the Aisin (Ram) 6-speed?

If its 3-yr like the engine warranty, we are past that already, since its an '08. Dealer looked up the VIN to check its in-sevice date, and we are already past the 3-yr mark. This truck is used almost exclusively in-town, so while its running all day long, it doesn't actually put on many miles.

I'm pretty sure its a sticking solenoid, but this is a new transmission for me, so I don't know how how serviceable or rebuildable the valve-body its.