My stock 1953 SM420 4 speed transmission has the wind back front seal. I can not keep it full of 90 wt mineral oil. By full I mean within a half inch of the fill plug. The tans operates properly however oil leaks out the clutch cover. In a few hundred miles it is below where you can touch with your little finger. Question how full should I fill this transmission?
Last edited by MtneerMike; 07/08/2016 9:50 PM.
