How often should u do a transmission flush and if the tranny feels like its slippin a bit will that help

 

is it a manual or auto tranny, if its slipping, it might just be low fluid if its an auto, but if its a stick it might be a bad clutch.

 

Judging by previous posts, I'd say auto.

Drain and fill every 30k is about good enough for normal wear and tear, you can do a flush if you feel it's necessary. There's a lot of stories about those killing an automatic trans because of dirt and grit, blah blah. If you shouldn't do a trans service when it needs it, i.e. burnt fluid, and you shouldn't needlessly be servicing a trans with clean, healthy fluid, does it never get serviced?

Basically, give it a shot. If it's already slipping, you'll be no worse off afterwards. Try Lucas transfix or something along those lines, see if that works.