turbo 350 in 66 dipstick

[65truckowner]

I put an aftermarket dipstick in my 66 chevy truck with a turbo 350 transmission and had a leak in my floor. I had the hardest time finding the leak and it ended up being the dipstick where is goes into the transmission is leaking. It only goes into the transmission about 1 and a half inch and is loose. Is there a way I can make this work with out leaking. I payed like 30 bucks for it and made a bracket for the truck. It looks great but I cant have the leak. It was suppose to be for the 350