I have a 1955 Cub and noticed a slow drip of what appeared to be gas and oil mixed. I can not find the source but it is dripping from the rear of the oil pan. Any ideas of what might be going on?
Thanks

Do you shut off the fuel valve when you shut the tractor down for the day??? If you don't I'd bet you have gas in the oil and if you run it that way you will be rebuilding the engine very soon. Common problem on tractors so you need to turn of the fuel when you park it or blow it up
Hobby farm

Look closely at the fuel shut-off/sediment bowl area. The drip may actually be starting there. "old" suggested shuting off the fuel .. I agree that should be done, but fail to see how the gas could get in the oil from there ..it would have to fill up the intake manifold before it found it"s way to a cylinder and into the oil. And that"s only if the over flow in the carb.was plugged.
If the motor was run with a dead cylinder,the un-burnt fuel could wash past the piston rings and into the oil.
Does the dipstick/breather smell like or shows signs of gas?
IronAddict

If, indeed, you have fuel leaking from the sediment bowl area (bad gasket, dirt in the valve, bad threads in the tank, etc.) it could be running down around the torque tube and mixing with leaking oil from a bad pan gasket or leaking rear seal.

Gas when it leaks like that vaporizes then goes up hill into the cylinders where it then turns balk to liquid and then goes down pass the rings into the oil. Very common problem on old tractors and I have seen it many times

Not at all uncommon. Worst potential is with a faulty seat on the float needle, which allows gas to run freely from an open or faulty valve at the bowl.

What would be a fix for this problem/
Thanks

That's a big question. Where to start?

You've had advice, all good as far as I've read, from different folks, suggesting the different things that might cause it. Read all that back over and go to it.

Just for starters, get a clean coffee can (wash it to get most of the coffee scent out of it) and draw a pint or so of oil out of the lower petcock on the oil pan into it. Swirl that around (pretend you're at a wine tasting) and give it a sniff to see if it smells strongly of gas.

If so you need to look for a leaky valve on the sediment bowl, a leaky float in the carb, or a leaky or obstructed float needle. I listed those in kind of reverse order of probablility, but it could be any one or a combination of any two or all three.

If the oil you get out doesn't smell especially heavily of gas, you could still have a leaky valve or fitting up around the sediment bowl that could be running down to mix with regular oil as someone suggested. Perfectly plausible. A jar under the sediment bowl might show up a dip in the valve or the connection to the line. But it might also be seeping out the thread of the bowl into the tank, which might not drip under the bowl but instead run forward down the bottom of the tank and show up further forward.

If the tractor is generally running okay, eliminate the carb and bowl, fittings and lines before worrying about valves and seepage past the rings.

But don't run the tractor long if the crankcase oil smells gassy, and especially not if the oil level is high enough that it runs freely from the top petcock (That's something to test before you do draw the sample into the coffee can for the sniff test). It could be gas or water raising the oil level. If a quick sample from the pan drain drawn into something like a mayonnaise jar doesn't show any water, it's quite likely over full with gas and you need to find the source.