Amsoil 75w90, 45K, 04 Chevy Tahoe

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Aug 29, 2011
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Texas
Fluid was replaced at time of sample.

Make/Model: GM Differential (Front)
Vehicle: 2004 Chevrolet Tahoe

Code:


OIL Amsoil 75w90 Amsoil 75w90 Unknown

MILES IN USE 45,029 29,386 Unknown

MILES ON UNIT 203K 158K 123K

SAMPLE TAKEN 4/25/16 11/8/13 5/3/11

MAKE UP OIL 0 0 0



ALUMINUM 1 2 7

CHROMIUM 0 0 1

IRON 85 133 346

COPPER 3 5 8

LEAD 0 1 1

TIN 2 0 0

MOLYBDENUM 2 9 82

NICKEL 0 2 4

MANGANESE 1 2 5

SILVER 0 1 0

TITANIUM 0 0 1

POTASSIUM 0 1 0

BORON 106 95 89

SILICON 31 36 38

SODIUM 1 2 4

CALCIUM 6 12 80

MAGNESIUM 0 2 10

PHOSPHORUS 891 862 579

ZINC 22 41 90

BARIUM 0 0 1



SUS @ 210F 67.3 78.6 56.0

Visc @ 100C 12.23 15.16 9.07

Flashpoint 415 415 370

Water % 0.0 0.0 0.0

Insolubles % 0.2 0.2 0.3

TAN 2.3 1.7 NA


Oil Analysis Comments:
The front differential on this Tahoe appears to be in very good shape, with low wear metal readings giving us no reason to suspect any internal problems. Iron, indicative of steel wear, is exceptionally low for the miles. The oil tested to be in good condition, as well, with viscosity appropriate for 75W/90, and no sign of significant water or dirt contamination. Solids (insolubles) read low at 0.2%, indicating very little oxidation due to heat, and the TAN of 2.3 shows that little acidity built up. Feel free to try 60,000 miles next time and check back then to see the effects.
 
The KV@100*C appears highly sheared from it's nominal 16.8 cSt .... I would replace said oil well before 45K miles.
 
You may want to use 75W-110 in the future if the shearing continues to give you a little more of a buffer.
 
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