Been getting decent puddle 4"x4" under the 78 2wd 351W (swapped) with a c6 the puddle seems to right under where the trans and block meet at the passenger side of trans right under the bolt at bottom side of trans case Rear main seal?? Or is there anything on the rear passenger side of a 351w that could leak. I thought maybe intake manifold gasket but replaced that already and still leaking.

 

Sure its oil and not trans fluid? If oil it could also possibly be valve cover gasket.

 

It's oil I replaced the valve cover gaskets when I did the intake but I'm gonna go check them right now

 

Valve cover at back of block is dry

 

Pull the access cover off front of tranny and look. If rear main is leaking it should be very obvious.

 

Never noticed one where is it?

 

First clean the motor and transmission.... Then there's stuff you can apply on the suspected areas. Wait a day or two and check. I'm not sure 100% but I have heard from baby louder or a white powder spray. But that's how I look for mystery leaks. Also pull the dipsticks of transmission and engine and compare them to the oil on the floor. Don't forget the power steering.