Depending on the mileage on the trans, it may be time to freshen it up. When does it do it? Does it slip in all gears non convertor lockup and when it locks up? Is the shift quality still good?
The weakest link has always been the trans in any of the pickups, and when you start putting more power to them, those problems get exposed.
Go to
www.allpar.com and look up their transmission section; it's Mopar only and they address the problems with all the Chrysler transes.
The other thing to do before you drop the transmission is to run some Auto Rx through it (
www.autorx.com). This product cleans slowly, refreshes the seals, unsticks solenoids and gets everything working right again without being harsh like the solvent style cleaners that you get at the auto parts store. Won't harm anything. Follow the instructions exactly, you won't regret it.
If you are still going to get a convertor, get a shift kit also.