91 Buick LeSabre Transmission

I have a 91 Buick Lesabre with about 180k miles on it. The transmission has been slipping here and there ever since I got it about 3 years ago. I talked to a guy at a transmission shop, and he told me that it was probably just low on fluid. Well, I have been adding fluid as I have felt it slipping ever since. I was driving last week, and it wouldn't go over 25mph and hasn't ever since. It acts like it wants to shift over into second gear and feels like it wants to, but something keeps it from shifting over. Any ideas?

I must admit, I have been driving it a bit here and there, but not much and not anywhere far. Just to work and back (about a mile). Could my transmission have gone out?

Welcome to AF. Well was it or it low on fluid or are you just adding fluid, did the trans tech check the car or just give you the fluid advice?

It was low on fluid at that time.I had been adding fluid as it would get low, but it had a slow leak that has gotten worse and worse. The guy didn't actually look at it, he just gave me some advice. he told me that I would probably need to have the pan tightened, and might need a new gasket or seal or whatever around the pan and might need a new screen. However, the leak got worse after I had the transmission flushed about 2 years ago.

Have it looked at to see where it is, no one can tell until it is inspected, how else can this be diagnosed?

Someone told me that it could be the vacuum line also. I don't know about that. I am supposed to go back and have a transmission shop look at it on Monday.

If the transmission needs to be replace, have any estimates on what that might run me? The car is in good shape other than the problems with the transmission problems I have been having.