I have a 1984 Toyota pickup I have a massive leak coming from above my tranny changed valve cover gasket not coming from half moons or anywhere out of the valve cover, I was assuming rear main seal but not sure!! I really need help to locate where it is leaking out when the truck warms up it leaks bad, and also what would cause fuel in the oil?? I was thinking carb any info is helpful thankyou!

 

take it down to the car wash and blow all the dirt and oil off of everything, a significant oil leak should be pretty easy to find when everything is clean.

 

I had this problem and it turned out to be that fat gasket on the fuel pump, a big chunk had broken out of it. replaced gasket problem solved.

 

I am assuming this is a 22R engine? A rear main seal would most likely show under the transmission at the bell housing area not above the transmission. The only sources of oil above the trans at rear of engine that I can think of would be either the head gasket or valve cover gasket.
The fuel in the oil is probably a bad diaphragm in the mechanical fuel pump on the passenger side of the engine near the front of the motor.