VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Correct Lubricant for Transmission & Rear Axle

I have a 1946 3600 ¾ ton truck that I am in the process of getting running. I am getting confused on the lubricant for the transmission and rear axle and having a hard time finding SAE 90 lubricant. I found an SAE 90W Mineral Gear oil API GL-1 at NAPA which seems to be okay for the transmission. The manual says not to use mineral oil lubricants in Hypoid rear axles. If I am reading the vehicle information kit correctly it looks like the 3600 has spiral hypoid final gears. So it sounds like I shouldn't use this in the rear axle?

I use 85W-140 in the TRANSMISSIONS AND DIFFERENTIAS.

Hi umoeker

As you can see, I also have a '46 3600, and love it!

You can use 80W-90 in both the transmission and rear axle.
GL-1 can NOT be used in the rear axle.
But GL-5 CAN be used in BOTH the transmission and rear axle.
And GL-5 80W-90 should be easy to find. 🙂

Gene's recommendation will work fine as well.
Just be sure it is a GL-5.

Please keep us posted on your progress... and maybe post some pictures?
I love pictures. 🙂

Thanks for the information, lot of different lubricants out there.

Thanks for the pic!

Very nice truck, you're going to have fun driving that!
I like the vehicles from this particular time period as they have the "old" look, but they have enough improvements over the 30's to be great daily drivers just as they are.
Enjoy!