O-Ring, Upper Shaft (LH)  3/16" x 1 7/8" ID - Fits Various:

Oliver White 1255, 1265, 1270, 1355, 1365, 1370, 2-50, 2-60

Minneapolis Moline

Allis Chalmers

Fiat Hesston

Long

rpls: 31-2902156, 70931949, 14471180, 10R431  

NOTE: Earlier models used 1 3/4" ID O-Ring (670664A)