Just a couple quick comments. Having been to the shandong factory that builds the KAMA branded tractors and toured their mahcine shops I can tell you that I saw NO equipment capable of holding "tenths" (ten thoustands or .0001") In fact, I saw mostly older manual machines, a bank of NC (NOT CNC) milling machines, that I could not idenify, but appeared to be out of the late 60s (6 or 8, maybe one still ran). They have their own foundry that appeared as if it was out of the 1930s. They did have test fixtures to "run in" assembled transmissions. The DF factory was different with late model, mostley Japanesese (and surprisingly a couple of US made HAAS machines) pallet chaninging HMCs etc. This was a big factor in my decision to go with DFAM for our AgTrac tractors. I had made my living as a CNC service tech and later as a sales engineer so the machine shop was a priority for me.
I didn't go to the Jinma factory and the Foton factory had no in-house machining.
The only yellow metals I have seen in the front end are in the differential assembly. there are brass thrust washers under the 4 smaller gears (spider gears) in the differential. While I have not seen these fail on a KAMA, I have reuibilt a few front differentials on Jinma 200 series tracors and in every case these brass washers had extruded out from behind the gears, this increases the clearence on the gear mesh and makes them prone to damage. I guess this is more from the increased pressure of loader work than a partiluclar lubricant, but if the sulfer in EP type oils does more than stain the brass, if it softens it or is abrasive to it, I would avoid using it. I have not had one apart, but suspect there are also brass washers used in the rear differential. I don't recall seeing any other bushings or parts made of brass. Our Agtrac 3024 had a full synchro transmission and the synchro rings are a brass alloy. I suspect "MT-1" may indicate manual transmission which are mostly synchronized these days. At least I use that to remember the spec when I order gear oil...