[nra1ifer]

At the rear of the tractor you'll see a plate held with 7 bolts to the rear of the differential. There is a gasket between the plate and the casting. To drain, loosen the bolts (they are about 3/4"-1" long), then wedge the plate off and let the fluid drain into a large drain pan. The hydro/trans has 7 quarts of fluid when full. You can either make your own gasket out of gasket material (like from NAPA), or buy one through a parts source. As for fluid, Case/IH Hytran Ultra is what you'll find recommended here. Once the new gasket is on and the cover replaced and tightened, add fluid through the plug that is about 3" down from the top of the cover. A 3/8" ratchet will fit in it.


Here's a picture I took of my 123 when I had it apart this summer, and a .pdf file of a tracing I took of a new gasket. Can be used to cut one from gasket material: