Hey, I know there's no problem mixing mineral and synthetic oils (per all the articles beating the subject to death), but my owners manual has a warning saying that mixing syn and mineral in the tranny can cause problems. (Just the transmission - not the engine or primary) Can't find any forums on that specifically. I'm going to switch to SYN3, and wondered if anyone had thoughts on flushing the HD Formula+ out first, or just draining it well, and stick the Syn3 in....... Thanks in advance for the help.......