Posted by Torvald [172.71.151.97] on Monday, December 04, 2023 at 22:57:17 :
In Reply to: Gear oil question posted by Galen [172.70.135.44] on Monday, December 04, 2023 at 08:12:45 :
The GL-4 designation of the Amsoil 75W-90 is a must because of the bronze bushings that are used in the transmission, so the question can be reduced to viscosity. I am currently using 75W-140 Royal Purple Maxgear and I really like it. My “later” B-3-PW series transmission has all new bearing assemblies and needles, but the countershaft and cluster gear were not replaced. I previously tried 80W-90 and 85W-140. I found that the 80W-90 was too thin for the eastern Washington summer heat (lots of noise), and that the 85W-140 was too thick for the Eastern Washington winter cold (difficult shifting when cold). The 75W-140 seems to work well at both extremes giving a transmission that shifts easily and is quiet.