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Since acquiring the M-1078 well over a year ago the transmission lube has been tested 3 times. Maybe this information will be interesting to others with these trucks.
The only materials that showed "interesting" levels were Copper and Iron. (values in ppm)
7/15/2015, iron 38, copper 153, mileage: 16974
4/03/2016, iron 69, copper 186, mileage: 21196
8/19/2016, iron 144, copper 260, mileage: 30692
Obviously I have driven it a lot (4600 miles in one month). This is the original oil in the transmission from when it came out of the military. Most of us assume that this is 15W40, based on the rumor that the military uses motor oil in the transmissions. Blackstone testing indicated lower viscosity than they usually see for 15W40 motor oil, "possibly due to shearing" for whatever that's worth.
Reading the columns, the values are obviously increasing. Wear products are accumulating, and it's time to change the oil. The important thing, based on Blackstone tests, there has been no sharp increased in wear, just gradual accumulation.
Iron is obvious, gears wear. So where does the copper come from?
I found this on the web, describing copper in engine oil, but these FMTV's have transmission cooler cores, quite possibly made of copper. Of course this is speculation at this time but Cat does say this can apply to transmissions.
"Per Caterpillar, high levels of copper found in oil analysis are a result of engine cooler core “leaching”. The zinc additive in diesel motor oils reacts with the copper cooler core tubes at high oil temperatures. This chemical reaction results in copper oxidation products forming on the surface of the tubes and then coming off into the oil as it washes over and around the tubes. Heat is a catalyst to this chemical reaction- the higher the oil temperature the greater the rate of oxidation and the longer the reaction process is sustained. This does not cause any damage to the cooler core, or to the engine. However, you will see the copper reading elevate to over 100 PPM. Copper is not a particulate in this case but is in solution in the oil. The PPM will start relatively low and increase over 100 PPM and stay at high levels for several intervals, and then return to normal. During the oxidation process, a hard film forms on the tube surfaces exhibiting the appearance of clear varnish. Changes in operating temperatures, and /or changing oil brands can chemically disrupt this film and begin the oxidative leaching processes again. This can occur in any system with a cooler core: Diesel or gasoline engines, Transmissions or Hydraulic systems."
Bob
The only materials that showed "interesting" levels were Copper and Iron. (values in ppm)
7/15/2015, iron 38, copper 153, mileage: 16974
4/03/2016, iron 69, copper 186, mileage: 21196
8/19/2016, iron 144, copper 260, mileage: 30692
Obviously I have driven it a lot (4600 miles in one month). This is the original oil in the transmission from when it came out of the military. Most of us assume that this is 15W40, based on the rumor that the military uses motor oil in the transmissions. Blackstone testing indicated lower viscosity than they usually see for 15W40 motor oil, "possibly due to shearing" for whatever that's worth.
Reading the columns, the values are obviously increasing. Wear products are accumulating, and it's time to change the oil. The important thing, based on Blackstone tests, there has been no sharp increased in wear, just gradual accumulation.
Iron is obvious, gears wear. So where does the copper come from?
I found this on the web, describing copper in engine oil, but these FMTV's have transmission cooler cores, quite possibly made of copper. Of course this is speculation at this time but Cat does say this can apply to transmissions.
"Per Caterpillar, high levels of copper found in oil analysis are a result of engine cooler core “leaching”. The zinc additive in diesel motor oils reacts with the copper cooler core tubes at high oil temperatures. This chemical reaction results in copper oxidation products forming on the surface of the tubes and then coming off into the oil as it washes over and around the tubes. Heat is a catalyst to this chemical reaction- the higher the oil temperature the greater the rate of oxidation and the longer the reaction process is sustained. This does not cause any damage to the cooler core, or to the engine. However, you will see the copper reading elevate to over 100 PPM. Copper is not a particulate in this case but is in solution in the oil. The PPM will start relatively low and increase over 100 PPM and stay at high levels for several intervals, and then return to normal. During the oxidation process, a hard film forms on the tube surfaces exhibiting the appearance of clear varnish. Changes in operating temperatures, and /or changing oil brands can chemically disrupt this film and begin the oxidative leaching processes again. This can occur in any system with a cooler core: Diesel or gasoline engines, Transmissions or Hydraulic systems."
Bob
