The Ford Barn - View Single Post

nkaminar · 03-24-2024, 03:10 PM

The 600W oil was good in 1930. (600W does not mean that it is SAE 600 weight.) But that was 90 years ago. The modern gear lube oil has additives that will extend the life of your gearbox, over drive, rear end, and steering box. The multi grade means that it will act like SAE 85 when it is cold and SAE 140 when it is warm. So you shouldn't have the problem with stiff shifting when cold.

There are two versions of the 85W-140 gear lube, G4 and G5. Mitchell recommends using the G5 which has twice the additive than the G4. However there have been some problems with the G5 in synchronized transmissions because when the additive wears off the synchro rings, which it is designed to do, it takes a little bit of the brass with it. It sticks a little too much. I have recently switched from G5 to G4 in my Mitchell overdrive and Mitchell synchronized transmission. (The additive wears off in preference to the metal underneath and then more gets deposited.)

03-24-2024, 03:10 PM	#4
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 4,067	Re: Gear Lube? The 600W oil was good in 1930. (600W does not mean that it is SAE 600 weight.) But that was 90 years ago. The modern gear lube oil has additives that will extend the life of your gearbox, over drive, rear end, and steering box. The multi grade means that it will act like SAE 85 when it is cold and SAE 140 when it is warm. So you shouldn't have the problem with stiff shifting when cold. There are two versions of the 85W-140 gear lube, G4 and G5. Mitchell recommends using the G5 which has twice the additive than the G4. However there have been some problems with the G5 in synchronized transmissions because when the additive wears off the synchro rings, which it is designed to do, it takes a little bit of the brass with it. It sticks a little too much. I have recently switched from G5 to G4 in my Mitchell overdrive and Mitchell synchronized transmission. (The additive wears off in preference to the metal underneath and then more gets deposited.) __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 03-24-2024 at 03:16 PM.