Is it worth the 11 to 12 dollars you spend on it to help with the slip in your transmission? do ya just throw it in with the tranny fluid after ya change it or just add it when needed?

I need a rear main seal without a rebuild kit - the gasket by the entrance for the drive shaft in the rear of the tranny - any other names for it so that I can find it? ;o

 

I don't have any in my transmission but the Lucas oil products are probably the best on the market. I run Lucas oil in my diff and have the oil stabilizer in my engine.