In the late '80s, there were problems with the FWD transaxles getting stuck in "Park", and Chrysler released a revised park rod for them. I think there were some 904 issues as well, so there might be a revised rod for yours. The inexpensive fix is to use the parking brake always, and then the park rod never gets bound up. If there is no revised rod available for your transmission, it is likely just wear to the parking pawl and the park rod. A new rod shouls still fix the problem, or make it less irritating.