> Redline MT 90 is GL-4 the multi weight 80-90 is GL 5 Just for clarity, Redline's full synthetic GL-4 manual transmission lube is available both in 70W80 (MTL) and 75W90 (MT-90). Their GL-5 gear oil is available in 70W75, 75W80, 75W90, 75W140 and 80W140. http://www.redlineoil.com/products_gearlubricants.asp?categoryID=7 Randall