My vehicle has 165K miles on it and the manual says the transmission fluid needs to be "flushed" I talked to the owner of a garage that specializes in Hondas and he says that flushing the tranny can cause a lot of problems (something about a filter and it could wreck the automatic transmission idk). Do you flush the tranny and ATF or just drain/fill?

 

Drain and fill. You never want to flush a transmission. I hope this is not the first time changing it.

 

Are you sure it says "flush"? I've looked in numerous Owner's Manuals for Hondas and Acuras and the only context I've ever seen where flush is used with automatic transmission is if the incorrect fluid is used. In that context, "flush" means drain and refill roughly three times. As Seanjordan20 says, you never EVER want to machine flush your transmission.