I finaly got 50 hrs on the air compressor part of my Air Pak.
Time for the first oil change, the next is 500hrs later. I did not reset my hour meter so that at 500 hrs I will change the oil again. The oil will only have 450 hrs, but from now on the time will be exact.
First, the book says 1.75 qts Mobil 1 synthetic ATF. Napa did not stock that oil.
O' Reillys did not stock that oil.
I finaly got it from the distributer.
I open the hood of the welder, drop the oil, change the filters, and add the 1.75Qts of ATF, and it shows low on the stick.
Then I see a decal under the hood that says 2.6Qts, that fills it up.
So to recap buy 3 qts instead of 2 and start looking for the oil early (45hrs or so).
Good Luck,