First off I run hd primary fluid in the primary and gear lube in the trans I just pulled my primary down to replace the inner primary seal and I'm pretty sure I could smell gear lube on the drain plug and in the fluid. Is it possible gear lube can migrate to the primary maybe it runs up the clutch push rod? Is this normal or do I have something going on I need to address?

 

Could be the main shaft seal, also I have heard that if you slightly overfill the trans it will run down through the inside of the mainshaft. Also check your trans vent tube make sure it is not plugged up

 

I'm going to check the vent tube I can't see how if the main shaft seal goes bad how would the trans fluid get in the primary