Transmission damage was not identified through oil analysis

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Good day.,
A laboratory made oil analysis to samples drawn from a Dana Spicer transmission (model 15.7 TE 32418-52). Below you’ll find previous analysis results from samples taken in Nov07 (981 hours) and March 08 (last sample 300 oil hours). Oil is Dexron III as recommended
(Nov 07/ March 08)
Viscosity 100C_ 5,29 cSt (March 08)
Water= 0% / 0%
TAN: 1,97 / 1,66
Copper: 0 / 0 ppm
Iron: 15/ 12 ppm
Chromium: 0 / 0 ppm
Lead: 7/ 0 ppm
Aluminum: 3 / 5 ppm
Silica: 3 / 8 ppm
The oil was changed and analysis was made (sample March 08). 2 weeks later (recommended oil Dexron III) a transmission failure took place. The client reported clutch discs and bearing damage. They are wondering (also myself) why this damage was not anticipated through oil analysis. Samples were taken with equipment in use or recently stopped.
Laboratory is certified and periodically evaluated since this belongs to a lubricant blending plant. Wear was measured through ICP Plasma (< 10 um) and values were very low. As I recall copper may indicate clutch material but still this metal was measured 0 ppm.
I don’t think asbestos could be determined.
Is it possible that a sudden failure could occur and it wasn’t possible to anticipate it ?
Any guidance or recommendations for further lab analysis will be appreciated.

4/14/084:52 PM

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geraldclsMember

Dear Xavier V
Please giee us a little more about the nature of the transmission, and the driver and driven load.
What is the range of operating temperatures for the equipment and the oil.
Do you still have any of the oil you drained?
Cant find particulars for Dana Spicer Transmission you specify. For more expert advice write to dave-wooton@wooton-consulting.com He's an Expert on Dextron II and III.

Sometimes Sludge and varnish can build up can be the culperit, but more info

4/14/086:42 PM

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rogerdaviesMember

Would expect some signs of failure in the oil analysis results if due to a wearing regime..
What is the clutch disk material?
Millipore solids may have helped to show clutch distress.
Viscosity has dropped a little from new(~2cSt)
Correct oil in use?(red and dex 111 ad pack) Drop in TAN by comparison could suggest different oil.
ICP values look low.
Maybe very sudden disc failure occured after sampling resulting in bearing damage.

4/15/083:15 AM

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enriqueMember

Many thanks for your replies.

Typical viscosity of this Dexron III lubricant is 7- 7,4 cSt. Sample of nov 07 is a different brand of oil. Reductions of viscosity (lowest 5,2 cSt) have been observed in other samples transmissions (dexron iii) using the current brand and it may be caused by shearing. How low is permissible/ expected the change in viscosity ?

Just talked to lab, they don't have milipore solids analysis. Today they checked the sample and reported the pressence of sediments at the bottom of the container... suppose this may be from the clutch material since they said it is black. Still cant' figure why copper didn't show warning values as expected?

4/15/088:05 AM

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bruce381Member

Sinec Dex III is not now licensed it maybe a cheaper brand with suspect qualities or more likley it is just catistrophic falure of which UOA will not ever show, basicly stuff breaks and sometime it is sudden and NO lab test will show that comeing only the wear trends.
bruce

4/16/088:46 AM

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bobkMember

What was the analysis of the fluid removed during the fluid change between November 07 and March 08? Since hours lower for March 08. Any check of lubricant condition? TAN can be misleading - indicative of acidic additve in newer oil but also indicative of oxidation - so both good and bad oils can have TAN values. Seen hydraulic pump running on DTE25 (loss of ZDDP, low TAN since phenol antioxidants still good) and C-130 aircraft gearboxes running on Jet II (loss of amine antioxidants, TAN just starting to increase)fail due to poor lubricant condition without production of wear metal.
What level does silica become of concern?

4/17/086:52 AM

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rttechMember

Hi

The parts should be root caused if not already for a catastrophic failure and if so I would expect unrelated parts in the transmission to be in very good condition and the parts involved in the failure should explain who could of failed first and subsequently damaged the others.

If however every part in the transmission is indicating heavy wear then back to the types of analysis being completed as there are several critical tests missing off your list.
We should be testing in the transmission applications for;

Basic Testing for should include;
ISO Particle Count, Viscosity @ 40°C, Water, Oxidation, PQ, ICP Spectrographic Wear Elements.

Transmissions;
Basic plus TAN @ 500 hours or 20,000ks Quarterly if light use
Gears, Differentials;
Final Drives Basic with TAN 500 hours or 20,000ks

This is a rough idea and one must consider the application.
If not a catastrophic failure there should have been enough trend change in PQ, Particle count to make one check further by maybe replacing the oil filter and examiningthe filter media and if wearing hard will be apparent,

Without the other tests what happened is almost impossible to predict and trend.

Regards

Rob S

5/1/082:17 AM

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michelleMember

Clutch packs in most older transmissions have been copper, lead based material, making it easy to diagnose a clutch pack wear problem from oil analysis results. Recently we have seen some transmissions with a graphite sort of clutch pack material which doesn't seem to show up in the ICP results. When a lab does not do a particle count test or debris check this wear can be missed. This is also true for the copper, lead wear particles if it is greater than 8-10 micron in size. With an increase in particle count (when done) the oil can be filtered through a filter pad and checked visually using a microscope. The new graphite clutch pack material looks very much like coal dust contamination (black) though. But it is visible. And they seem to be very sensitive to water contamination. If there was a sudden ingress of water, sudden failure could occur. Did you get a sample analysed after failure to check for contamination of any sort?

5/13/0812:43 AM

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jezzMember