Well got one helll of a head cold and just didn't feel like going back out in field after supper and took a minute to flip thru a couple books in the shop. Was some good stuff in a binder of service school notes, I do have more info somewhere else but for now there is this...and this covers all models of the 12 speed, no matter which tractor, as only diff is number of teeth on a few gears between V8 and inline 6 engine models. Early trannies have the coarse splines on the shift collars and shafts, Series II and up have fine spline. I know about the gears and splines from looking into replacement tranny for my Series III 875. Bought a whole 750 Series II tractor with 5100 original hours but with a bent frame, cheaper than the wreckers would sell me just a tranny, still haven't changed it, everything still works in my old one, I just don't have the bottom four gears, about 4mph is as slow as we can go lol.
Operating pressure is supposed to be set max 15 psi. Pressure is set by what they call a spring loaded check valve which is supplied directly from the rear manifold and screws into tranny case either just above shift cover or into the top of the cover itself on the right hand side. It simply dumps excess oil directly to sump.
The warning system on them is triggered at 4psi, so in other words, anything 4 or lower hot at idle is below spec.
Not sure why they are so elusive about the tech on that lube system, but I have a couple more books yet and I know its somewhere in one of them about the hoses. Thinking the flow test numbers might have come from Scott so they be buried in an email somewhere I guess. I seem to recall operating pressure to be 12-15 psi when hot as well, where that memory originates I well just can't remember lol.
There are rebuild kits for those pumps, but might be better in long run to just get a new pump.
Contracts are made to be broken, a handshake is the law of God.
Last edited by albertabuck; Today at 12:00 AM.
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