model a fluids - rear diff?

what are you guys with early fords running for rear diff fluid? anything special, or....?

Searched around but didn't really find much.

Simple question, but I wanna get the right fluid in the rear diff of my coupe.

Also, the rear diff appears to have a square opening in the plugs, looks like 3/8" but it's slightly oversized and 1/2" is too big. I can get them out one way or the other, but is it something specific that it takes? or is it just 3/8" and mine is hogged out?

Thanks guys

 

600 wt diff oil
guess you could use stp too
3/8 ratchet should work
tk

 

You can use any modern gear oil in there. I have a v-8 banjo. I run whatever it is 75-90? I know another guy that runs synthetic gear lube in his banjo rear, says it runs cooler.

 

I've had great luck with straight lucas oil stabilizer. No oil, just stabilizer

 

Im running 85 W90 gear oil if i recall and its not a 3/8 or half, and mines a model A banjo

 

Model A Fords took 1-1/2 to 2 quarts of 600W oil in the rear diff from factory.

 

i get it from snyders. real thick so it stays inside.

 

ive ran 85w 140 in my trans and rear it works well but they tend to leak some hardly noticible. 600w works good to and doesnt leak as much. if its rebuilt or re sealed id run the multi weight considering your in a colder climate.

 

X2, I agree!

 

Awesome. Thanks for the info!!