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Transmission Oil Analysis

Discussion in 'Technical Discussion' started by jrp4783, Jan 2, 2015.

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  1. jrp4783

    jrp4783 Member

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    Detroit, MI
    I recently received my oil analysis results for my transmissions. The boat is a 2000 50' Post with ZF IRM350PL transmissions. When I look at the trend of the starboard sodium readings and molybdenum, I notice that they are starting to increase. For comparison I also included the port transmission values. Anything to be concerned about? Trans oil cooler leak? The boat has been in fresh water for 3.5 years. Thanks

    Oil Sample Trans.png
  2. Capt J

    Capt J Senior Member

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    Is it currently in saltwater? When was it in freshwater? What are the rest of the readings for the sample? Are you sure the place that is checking the samples is doing a good job? Because I find it really odd the port trans has zero values for the sample
  3. jrp4783

    jrp4783 Member

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    The boat has been (and still is) in fresh water since June of 2011. I'm not sure how to tell the capability of the place that is doing the samples. My mechanic sends them out to a company that does the analysis. Please see the entire readings below:

    full readings.png
  4. Capt J

    Capt J Senior Member

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    It's obvious that it was a long time that the gear oil was changed prior to 2010 by your readings. I honestly wouldn't worry about what you're seeing now. 24 PPM of sodium is nothing and could be from a drop of sweat or etc. All of your readings look good from what I see and all of your wear metals are low.
  5. jrp4783

    jrp4783 Member

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    Thanks for the input Capt J. You're correct about the prior oil change to 2010. I believe it had been 3 years (previous owner).
  6. SFS

    SFS Senior Member

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    Short of asking questions directly of the lab that did the work (what analytical methods were used, what the QC results associated with this specific analysis looked like, and getting a feel for the strength of the lab's overall QA program), it's difficult to assess the quality of the analysis. If it is a reputable lab, that does a lot of this work, you should be able to trust the results.

    As a QA chemist with 35 years in labs, I did notice two things that are noteworthy.

    1) The concentrations of many metals dropped between the 2010 and 2013 samples. This could be the result of an oil change, but you speak above about "the prior oil change to 2010". Am I correct in assuming the the oil was ALSO changed sometime between the samples analyzed in 2010 and the ones analyzed in 2013?

    2) The way that the results have been reported for calcium (Ca) and zinc (Zn) changed from 2010 to subsequent years. For 2010, the results were reported as greater than 300 (which is not very helpful, as the result could be ANY number greater than 300). For the two later years the results were much more precise, and covered at least one more order of magnitude. There are several potential reasons for this (many of them technical), and you can PM me if you're interested. However, the most likely reason for the difference in reporting is a change in the lab your mechanic used.

    You may not care about a change in labs, and there is likely no reason to care, but I always recommend sticking to one lab if you are happy with the service you are getting and you are confident in the results. Historical continuity with one lab helps eliminate one of the variables to examine if you have to start troubleshooting a problem.
  7. mikewheels

    mikewheels New Member

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    When you pull the oil samples, are the transmissions up to temperature? According to what I read, when taking engine or transmission samples, the oil has to be up to temperature. I am waiting for my transmission oil results on my 2000 50 foot Post. When I receive it I will post it here.
  8. Capt J

    Capt J Senior Member

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    The reason you want to pull them after everything has been running is so that everything is suspended in the oil. With oil samples, I have also seen people pull them cold from the oil filter or out of the dipstick tube after the motor has run.
  9. Worthy vessel

    Worthy vessel Member

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    I have a Sea Ray with Cummins 5.9 diesels and ZF trans. The gauge said that the port transmission was running 14 degrees hotter than the starboard. I checked the temp with a digital gun and the gauges are correct. The engines both run at the same temp.
    Fluid was 8 oz low in the port engine and I added fluid. I also soaked the transmission cooler in barnacle buster. These
    2 things improved the temperature difference to only 9 degrees. Should I worry about this difference. The transmission fluid looks perfectly clear.
  10. motoryachtlover

    motoryachtlover Senior Member

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    I was told that the port gear would always be a little hotter than the stbd because it was running an extra set of gears to run the prop the opposite direction that the stbd. Hope that makes sense.
  11. Worthy vessel

    Worthy vessel Member

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    Wow, that makes a lot of sense!
    Thanks