rolls(a little) in Park

96 Sunfire, 121K auto tranny. seems to shift fine in all gears but when in Park it'll roll back. Trans Shop says $500. to replace some stop inside and may lead to other probs if not fixed.... just changed the fluid. Does this sound legit or will linkage adjustment correct it? Thanks for any reply.

How far does it roll? Adjusting linkage will not correct this problem since the mechanism that holds your car in park is located inside the transmission. It works in a similar way to your front door dead bolt. If your car only rolls an inch, then I wouldn't worry about it just yet.