(7/5/2022 7:54:17 PM)
RE:1935 Massey GP
This has been a question asked over and over again. This was a design fault in my opinion, they later fixed it when they came out with the overhead valve tractors. They drilled a plug hole just to the right and above the belt pulley housing where it bolts on the right side of the transmition. You can take this plug out and fill with oil through the 4x6" cover just under your knee when sitting on the seat until the oil runs out then it is to the correct leval.
I believe I have one or two of the earlier flathead GPs that have been drilled out and tapped a 1/2" plug into the side of the transmition to make it easier to get the correct oil leval.
If you have the transmition compleatly empty it should hold 4 gal and 1 quart of oil same as used in the engine as they can flow back and fourth as there isn't really a rear main seal on the crankshaft.
If you haven't dropped the lower pan off the bottom of the transmition I suggest you do so as you will find you may need a putty knife to scrape out the gunk hanging on the ledge in the transmition case, usually enough to fill a dog dish in there.
Here is a picture of the pipe plug location on an overhead valve tractor.