Converter problem?

Thanks for your replys.
I have the idle @780 as any lower it will stall in reverse. THe car had a fresh tune up this spring and has been running great. Did suffer a coil failure ( 1 month old) last weekend same time this trans problem started. Talked to a trans shop and he feels a pump seal may be leaking and pumping oil where it should not be when in reverse. Justa guess though.