I have a 350 turbo chevy trans in my 36 Ford. I am going nuts trying to stop trans leak. I've changed the manufactures gasket three times myself then bought an aluminum pan changed gasket again ...still leaked.
I finally took my car to AAMCO they changed gasket and it still leaked with aluminum pan. I then decided to let AAMCO try with manufactures gasket.....guess what , it still leaks.
I've tried cork gaskets and rubber gaskets. I've put a metal ruler on trans to make sure its true and its OK.