Classic/Antique Car Repair: whinning turbo 400, turbo 400, th 400

Question
I have a 350 chevy with a turbo 400 transmission in a 57 chevy. The car was stored for 20 years. After getting the car out and running the only problem i am having is the transmission makes a whinning(sounds just like a supercharger)noise for about 45 seconds when started cold. After that the noise stops and all is fine. Shifts are firm and solid. I changed the filter and had no improvement. Thanks for your help.

Answer
Hi Arn:
Sounds a lot like the fluid not getting to the gears fast enough.
Is the transmission fluid at the full level? Remember, you have to
drive TH-400 about 20 to 30 minutes to warm up the transmission before
you can check the fluid on a level surface. This is the only way to get
a true reading of he fluid level.