Gear Lube Analysis Numbers

[John Berger]

Here are the numbers on the gear lube analysis. Miles on lube - 38K of which approximately 30% was towing. Lube was Amsoil Series 2000 75W-90. First number is my oil, second number is universal average



Aluminum 1 2

Chromium 7 3

Iron 278 514

Copper 2 2

Lead 0 0

Tin 0 0

Moly B 0 3

Nickel 1 3

Manganese 8 12

Silver 0 0

Titanium 0 0

Vanadium 0 0

Boron 75 141

Silicon 93 152

Sodium 8 8

Calcium 7 19

Magnesium 1 2

Phosphorus 1086 1411

Zinc 40 57

Barium 1 3



SUS Viscosity @ 210 deg. F

should be 67-80 was 73. 4

Flashpoint should be >375 Was 380

Water should be <0. 05 Was 0. 0

Insolubles should be <0. 6 Was 0. 4



"Comments: Wear and silicon read at about half the universal average levels for a lube oil from this type differential. The iron wear looks okay but we would rather see the silicon down at around 50 ppm or lower. If we didn't know better we would think this was OE fill. Insolubles and the viscosity of this lube oil were normal and we found no moisture in the sample. Suggest changing this lube oil to limit abrasion for the next use cycle. "



The silicon levels may be easy to explain. I had two bad pinion seals during the run on this lube. I had no makeup oil at anytime prior to the analysis. Last weekend I dumped the lube and filled it up with Amsoil Series 2000 75W-140. After reading this, it turned out to be a good call.



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1999 Dodge Ram 3500 Quad Cab 2wd; 5 spd; 4:10 LSD rear; Mag-Hytec differential cover; US Gear EGT and Boost gauges. Stewart Warner Fuel Pressure Gauge with dual senders, Westach Oil Temp Gauge for differential. Rancho 9000's on order, PowerEdge EZ Box, Amsoil foam air filter and synthetics in the motor and differential. Cummins Power, don't leave home without it



[This message has been edited by John Berger (edited 05-17-2001). ]

 

[JJW_ND]

John:

I have had very high silicon levels every sample because of the Silicon sealent I used. Had nothing to do with the "dirt" version of silicon.

Also, What was your TAN?

TAN is the gearlube counterpart to TBN. Only higher readings are bad.

I have had several rear diff. samples flagged with TANs getting up their. Were as the Iron and other wear elements were just fine.

My last Series 2000 test came back great even at 50K miles. Very good oil.

jjw
ND

 

[John Berger]

I don't know. I used Blackstone Labs and I don't believe that they test for that which is why I'm going to Oil Analyzers for my next oil analysis.

 

[TwoSlick]

In case anyone was wondering, "TAN" stands for total acid number and it's generally used to define the allowable life of gear lubricants and automatic transmission fluids. As the fluid degrades from heat and oxidation, the TAN continues to rise, eventually reaching the limit. This can happen significantly before the limits on wear metals and other contaminents are reached, so you definitely was to make sure the lab you're using tests for this variable.

I would agree with the comments made about the silicon(e) - it is generally from the gasket materials and not from "dirt", unless you are doing lots of off-roading, or have a bad seal ... .

Boron is used in small amounts as part of the additive package in some oils.

TooSlick