I will be rebuilding my SM420 4-speed transmission very soon and I would like to get some opinions about what oil I should use in it when it's rebuilt. The Novak site where I ordered my rebuild kit recommends a type GL-4 rated oil from Stalube or Redline, but they do not specify the visosity rating or how much I will need. Does anyone recommend any particular brand and viscosity? How many quarts will I need for my freshly rebuilt SM420? I found a place selling Redline MT90 Manual Transmission Fluid, which is a 75W90 GL-4 for $8.95 a quart.
http://www.turnermotorsport.com/html/detail.asp?PRODUCT_ID=MT90 The 1954 service manual states that a SAE 50 oil should be used. Any thoughts? Thanks.
Jim
