Multi pattern TH-350, deep pan, from a 78-79 chevy van. Trans is now bolted to a stock 307, stock converter, S-10 chassis under a 50 chevy pickup. I changed the fluid, filter (ATP B-45), front and rear seals then went for a drive. Fluid was dark red, with a slight burn smell. The trans shifts firm and at the rpm points you would expect. There is a whine when the trans is cold, (like might be described as a Powerglide whine) the whine gets quiet as the trans/motor warm up. The whine never really goes away but gets significantly quieter as things warm up. The shifts feel the same and shift at the same point regardless of temperature.
How much concern should I have about the whine?
I'm planning to have my old 350 rebuilt at some point but need to rebuild my "car budget" first. LOL.