What is the correct axle oil for the worm drive? Also is there a safe way to flush the old fluid without disassembly? Thanks!
85W-90W GL-4 gear oil.
GL-4 is a little harder to find than the GL-5 but is supposed to be safer for bronze. NAPA carries the Sta-Lube brand of GL-4.
Is this the fluid used in car Ruckstells? If so, I've been told not to use it as it's too thick to get up to the worm gear and roller bearings at the top.
Hello Chris, this is as Justin says. I made a thread about this several years ago that explains this. Just try to get the GL-4 that won't bother the Bronze parts. There is also a prelube plug (added around 1924) on the back of the Worm for the thrust bearing. Use this plug to fill this compartment up if your differential is just rebuilt or has been setting a few years. Ford had a lot of changes in this area it seems to prevent this bearing from failing.