Right now I am using 5w-20 in my d series tranny but my 3rd and 5th are starting to grind at high rpms. So I took a trip out to advance to look for oil and they only carried Pennzoil synchromesh but it was with all the other gear oil like 75w-90. I was wondering if these (syncromesh/gear oil) have any pros/cons in honda transmissions?