I was catching up with an old buddy, talking bikes & trucks (and kids & grandkids) and in talking about new stuff he said he likes syn products in his transmissions and diffs but not in the engine because today's gas has more dirt and junk in it than back in the 80s. He's a dino/3k OCI guy since he wants the dirty oil out regularly and synthetic would do no good. This guy is fastidious about his stuff. Just doesn't seem correct to me but I have no proof so I didn't debate it. Thoughts?