Continued to follow the Blackstone recommendations and extended this one to 50K. Will be pushing towards 60K for the next OCI. This truck does a lot of pulling, but only occassionally is it at the rated limit. Overall pretty happy with the results, especially the PPM / mile trends on Iron.
Make/Model: GM Rear Differential
Vehicle: 2004 Chevy 2500HD
Code
OIL SVG 75w90 SVG 75w90 SVG 75w90 VAL Syn 75W90
MILES IN USE 50,662 40,069 39,780 29,976
MILES ON UNIT 236,861 186,199 146,130 106,350
SAMPLE TAKEN 4/29/19 11/24/15 7/3/13 10/20/11
MAKE UP OIL 0 0 0 0
ALUMINUM 1 2 0 1
CHROMIUM 0 1 0 1
IRON 104 87 59 189
COPPER 0 0 0 1
LEAD 1 0 0 0
TIN 0 0 0 2
MOLYBDENUM 0 0 0 0
NICKEL 2 2 2 6
MANGANESE 4 3 4 13
SILVER 0 0 0 0
TITANIUM 0 0 0 2
POTASSIUM 0 9 0 1
BORON 76 76 109 284
SILICON 27 46 12 5
SODIUM 3 2 3 15
CALCIUM 19 19 24 64
MAGNESIUM 4 5 0 3
PHOSPHORUS 876 894 926 2192
ZINC 15 10 14 37
BARIUM 0 0 0 1
CADMIUM 0
VANADIUM 0
ANTIMONY 0
LITHIUM 2
SUS @ 210F 81.3 86.9 73.1
Visc @ 100C 15.84 17.22 17.9 13.7
Flashpoint 410 430 375
Water % 0.0 0.0
Insolubles % 0.1 0.1 0.3
TAN 2.7 2.9 2.10
Oxidation 45
Nitration 4
Oil Analysis Vendor Comments:
Silicon dropped and the increased iron isn't surprising. It tends to track with oil use, and on a per-mile basis, this level is impressively low. For reference, universal averages show 9.1 ppm/1K miles while this differential produced just 2.05 ppm/1K miles during this run. Other metals look good too, showing no mechanical problems. The viscosity was the only mark, reading just slightly thick for 75W90 oil, which isn't a problem at all. Clearly, internal parts didn't seem to notice. The TAN shows mild acidity at 2.7. Go ahead and try 60K miles or so next time. Nice!
Make/Model: GM Rear Differential
Vehicle: 2004 Chevy 2500HD
Code
OIL SVG 75w90 SVG 75w90 SVG 75w90 VAL Syn 75W90
MILES IN USE 50,662 40,069 39,780 29,976
MILES ON UNIT 236,861 186,199 146,130 106,350
SAMPLE TAKEN 4/29/19 11/24/15 7/3/13 10/20/11
MAKE UP OIL 0 0 0 0
ALUMINUM 1 2 0 1
CHROMIUM 0 1 0 1
IRON 104 87 59 189
COPPER 0 0 0 1
LEAD 1 0 0 0
TIN 0 0 0 2
MOLYBDENUM 0 0 0 0
NICKEL 2 2 2 6
MANGANESE 4 3 4 13
SILVER 0 0 0 0
TITANIUM 0 0 0 2
POTASSIUM 0 9 0 1
BORON 76 76 109 284
SILICON 27 46 12 5
SODIUM 3 2 3 15
CALCIUM 19 19 24 64
MAGNESIUM 4 5 0 3
PHOSPHORUS 876 894 926 2192
ZINC 15 10 14 37
BARIUM 0 0 0 1
CADMIUM 0
VANADIUM 0
ANTIMONY 0
LITHIUM 2
SUS @ 210F 81.3 86.9 73.1
Visc @ 100C 15.84 17.22 17.9 13.7
Flashpoint 410 430 375
Water % 0.0 0.0
Insolubles % 0.1 0.1 0.3
TAN 2.7 2.9 2.10
Oxidation 45
Nitration 4
Oil Analysis Vendor Comments:
Silicon dropped and the increased iron isn't surprising. It tends to track with oil use, and on a per-mile basis, this level is impressively low. For reference, universal averages show 9.1 ppm/1K miles while this differential produced just 2.05 ppm/1K miles during this run. Other metals look good too, showing no mechanical problems. The viscosity was the only mark, reading just slightly thick for 75W90 oil, which isn't a problem at all. Clearly, internal parts didn't seem to notice. The TAN shows mild acidity at 2.7. Go ahead and try 60K miles or so next time. Nice!
