How much gear oil for a 1928 GB-W rear axle?

[Gary_Ash]

I started filling the rear axle from a 1928 GB-W in my Indy car with 80-90 weight GL-5 gear oil.  I thought a couple of pints should do it, but I've put two quarts in and it's nowhere near full.  Anyone know what the capacity is supposed to be?  I think the service manual says "fill it until it runs out the hole."  That's always been what I've done in the past with other cars.  Should I buy two more quarts or more than that?

 

[nvonada]

Two quarts seems like a lot.  Can you feel it if you stick your finger in there?  If it were running out past the axle seals you would have seen it by now.  

[ArticiferTom]

It may take a little more . My truck small UF takes 3 -1/4 pints . Fill to bottom of hole . I personally go 1/4" less . Remember your filling the bottom of taper on axle also . i also use 140 wt  book states 160 wt .  

  just looked up other DB/GB trucks that take up to 6 quarts .Also of 600w  Mobiloil C or equivalent .

 Sorry not  a very direct answer . just show could be anything . The common is bottom of hole for level to keep it out of wheel bearings .

Edited March 30, 2021 by ArticiferTom
and thoughts (see edit history)

[Gary_Ash]

I put in the third quart, level was just below the hole, so I stopped there. I really hate the stink of gear oil, hard to wash the smell off my hands. 

[Aussi John 1]

You should check with an oil company.

 

They should be able to tell you the quantity and also the type.

 

I don't know what GL5 means, but you should not use modern oil in old cars as the chemicals damage some of the surfaces. As far as I know it should be a straight 90 gear oil, but check with the manufacturer, 

[rbk]

I just called Studebaker and it says that their number has been disconnected and I wonder why.

 

[SC14MOC]

The issue with GL5 oils, as highlighted by Aussi John is that they may contain "harsh"EP additives (eg sulphur compounds) that attack yellow metals eg copper, bronze. There are some around that say they are safe with these metals, so just check with the manufacturer that your oil is safe with the metals in your diff, as previously advised.