I've been changing oil, trans fluid and rear end fluids for almost 40 years..... I've NEVER seen foam come out of anything!
The fact is. Oil is made to work under extreme pressures like when the combustion chamber fires and squeezes the tiny oil film between the bearing and the crank. That is one of the things that oil is manufactured to do/protect.
Spinning a few gears over touching the top surface of the oil isn't a viable test to me... sorry.
Just my opinion, others will vary.
Danford1
