Transmission Problems

Hello everyone. I have a 1995 caddilac SLS. My tranny is slipping from first to second gear. Also it makes a Humming noise. I took it to a tranny repair shop and he tested it and said that after he tested it that it already had a shift solenoid kit put in it. This car only has 75,000 miles on it and now he is going to give me a quote on a remanufactured tranny. Im still waiting for the quote form him he will tell me on Monday. The thing is I have been told by 2 reputable mechanics to have the flush and filter changed fiirst, but the tranny mechanic said I will be wasting my money. Can anyone give me some advice on this??????

Have you checked the codes yourself to see what they read?

Everyone told me I needed a new tranny too. It wound up being a broken solenoid.