Have a 1954 ford truck all original with 239 ohv and 3 speed standard trans. Was getting a pretty good puddle of oil underneath after each drive so replaced rear oil seal. I have done several over the years with good luck. After changing still had leak as I staggered the neoprene seal and oil them up pins drove in good on side seals as well. Got under truck and looked and oil did not look like it was coming from rear main but dripping out the small bottom hoe in the fly wheel cover pan. Is there a front seal on trans input shaft that could be leaking.

 

You don't mention which 3 speed you have for me to get specific parts, but there is an oil slinger disc behind the front transmission bearing - there is no oil seal.

 

You "should" be able to tell if it's engine oil vs gear oil by the odor. That said, try dropping the cover and see what the flywheel and clutch look like. The rear main seal retainers on these things can be problematic. They have to be staright and concentric. It's hit and miss replacing the RMS on a Y block in the vehicle. Everything has to be oil free so the the side seals need that dab of RTV can seal.