I have recently acquired a 1965 Ford F100 with a 1969 Mustang 302 V8. The previous owner says he was told it had a pre-FMX transmission in it possibly a 1954 model. The warranaty plate on the door identifies the transmission as "G" which from what I can tell is a "Heavy Duty Cruise-O-Matic." Can anyone tell me how to find out what this transmission really is? This transmission shifts hard and strong and I definitely want to keep it but I can't even tell how to determine how much fluid should read on the dipstick. I was told it uses Type-F fluid.