Noisy rearend 69 barracuda 318 car

I just came out here in the garage and the rear is a 7.25 I don’t know if it makes a difference with the preload or not in the service manual you are supposed to use a additive the same they use for 8.75.
Pat

t
Well,7 1/4 rears are a dime a dozen so before you spend a nickle on this one see what you can get as a replacement.People actually give them away !