Well being naturally curious and usually looking at things with an open mind I did a tiny bit of research on that Gear Oil. But it left me with my mouth open and I have absolutely no idea what they are talking about.
Gear Oil, 600 XP 460, Size 1 Gal, Size/Net Weight 240, Viscosity Index 100 cS, ISO Viscosity Grade 460 cSt, Viscosity 30.6 cSt SUS @ 100 F, Flash Point 392 F, Pour Point 16 F, Extra High Performance, Outstanding Extreme Pressure Capabilities, Load Carrying Properties, For Industrial Spur, Helical and Bevel Enclosed Gears, Flender BA 7300, AGMA 9005-E02, DIN 51517 Part 3, ISO 12925-1 Type, Textron Power Transmission Grade E7, Mueller Weingarten DT 55 005 CLP 460
And where in the world do the idea that a 600w gear oil was called for in a rear end or transmission? Just because the 60 or 80-year-old gear oil that one finds in the gearboxes is as thick as molasses doesn’t mean that’s the way it was when they first filled them. This gear oil is meant for enclosed gears in heavy equipment and not to lubricate ball and needle bearings like we find in transmissions and differentials. S.A.E. 90 gear oil was specified for most of the transmissions, rear end and steering boxes back in the day. Today we have multigrade oils such as 85 or 90w-140, which is perfectly adequate as a replacement of the early straight weight gear oils. Heavier is not always better and can lead to cavitation and actually starve the bearings of lubrication. There is no way this heavy of a lubricant is going to be able to lubricate a shaft in a bushing, there just simply isn’t enough clearance to allow it to flow.
For my steering boxes I still think I’ll stick with “Penrite Steering Box Lube” or S.A.E. 90w-140 in a pinch. And the later for my transmissions, and differentials, they’ve never failed me yet.
And if you have a problem with the lubricant leaking past your seals in your transmission, differential or steering box then you have worn bushings, bearings, seals or improper preload adjustment on the bearings.
Denny Graham
Sandwich, IL
