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ZF350A Transmission

Discussion in 'Technical Discussion' started by CSkipR, Sep 30, 2014.

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  1. Beau

    Beau Senior Member

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    Does this gear call for a straight 30 wt oil?
  2. CSkipR

    CSkipR Member

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    Okay will try and answer all questions. Sodium was 2 on port and 3 on sb. Iron was 30 & 31. The ZF filters had product number and ZF on them. Came from Man distributor. Man gauges show both temp and pressure. Haven't used boat since oil change, weather sucks. The sample was of the old oil and not sure how many hours was on the trans oil. Could be more than 400hrs.
    Oil was Mobil 1 Delvac 5-40w same as engine oil before changing. SUS Viscosity was 53 & 55%. cST viscosity was 9.04 & 8.29. Report from Blackstone was good.

    When I talked to ZF last week they said 40w, 30w or the existing 5-40w could be used. They said most use a straight weight.
  3. Capt J

    Capt J Senior Member

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    I should really hope that there is not any unburnt fuel in a ZF gear or something is seriously seriously wrong.

    Generally diesel oil turns a dark brown/black after running a few hours on most engine brands, usually within a few minutes of it running. You never do get more than 90% of the oil out of the engine in a yacht, between what is trapped in the coolers, lines, and pan that can't be sucked out. Certain brands of engines, the oil tends to stay very clean with the oil looking like it came out of the bottle for the first 50 hours or so. Usually Yanmar's, Cummins, and Cat's stay very clean. The dark brown/black is caused generally by unburnt hydrocarbons, or poor combustion in the combustion chamber of fuel. I've been told that a multi-grade oil as it ages and breaks down it works it's viscosity towards the lower number (for example 15w-40 will work it's way to a viscosity of 15 weight as it ages). In a gear oil sample, I'm focusing on sodium content (a leaking cooler or could be just from a engine room that has a lot of salt in the air, iron (high iron would be an indication of high moisture in the gear oil causing things to rust), and other wear metals such as copper and zinc. A gear never runs hot enough (or shouldn't) to burn off the moisture that ever so slowly accumulates in the oil from condensation.

    Cskip has been running technically what is considered the wrong type of oil (Mobil delvac synthetic 5w-40) and was the primary reason he changed it, but the oil also has 400 hours on it. Conventional 40W oil is generally recommended by ZF in Florida (cold climates 30W).

    rcrapps=The ZF filters are all white and have just a small ZF logo and the part number painted on them

    The sodium and iron look good for the oils age, were any of the wear metals over 50 ppm?
  4. captholli

    captholli Senior Member

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    Could this be the difference between a scavenging 2 stroke or 4 ??? Most brands...
  5. CSkipR

    CSkipR Member

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    No fuel or contaminants in the oil, that would include fuel, etc. Capt J the only one slightly over 50 was copper and it was at averages.
  6. CSkipR

    CSkipR Member

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  7. Capt Ralph

    Capt Ralph Senior Member

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    You speak 750 & VMS?
  8. Marmot

    Marmot Senior Member

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    Saybolt viscosity is not given as a percentage ... the way you posted it read as if the viscosity was 50 odd percent of normal. That 50ish number is the reading in Saybolt Seconds ... the time it takes in seconds for specific volume of oil at a specific temperature to flow through a specific sized orifice.
    The figures you provided show an oil slightly more viscous than 40wt at 100*F.

    You must be very precise when talking about the readings shown on an oil sample report.
  9. Capt J

    Capt J Senior Member

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    That and how clean (fuel/air ratio, atomization)the motors run on cold startup, normal operation (and operating temps-coolant), and how they're run. 2 strokes such as DD's would dirty the oil quicker than 4 strokes from what I've seen. Some seem to run dirty when cold with unburnt smoke coming out of the exhaust such as CAT 3208's but their oil stays pretty darn clean in color. The amount of blow-by is a large factor as well. Generally oil isn't changed because it has broken down, it is changed because of all of the contaminents in it.

    Cskip, sounds like your oil has been doing a good job at protecting the gears. You didn't state how many years you have on it. I prefer to change gear oil every 2 years, personally. It's about $200 between the 5 gallons of oil and the 2 spin on filters on a set of zf's like yours, cheap insurance when a rebuild is $12-16k a gear.
  10. CSkipR

    CSkipR Member

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    Capt J,
    I've owned the boat since 08 but the boat and engines are originally 05. Agree with changing the trans oil & filters every 2 years.
  11. Capt Ralph

    Capt Ralph Senior Member

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    What does the book (factory manual) say? I'm an ole TD guy. My 514s spec 1000 hours. Of course we love to baby our equipment when we can (and I do), but changing to often could be a lil expensive when not needed.
    Pull an other sample next year and again when the 2 year time comes again. It may be still clear and under the factory recommended interval.
  12. Capt J

    Capt J Senior Member

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    I forget exactly what the manual says. I know the manual says every 1000 hours, but doesn't have how many years if I remember correctly. Which every 1000 hours would be fine if you're accumulating them in a year or two (commercial setting). The guys from ZF North America all have told me they recommend changing it every 2 years.
  13. CSkipR

    CSkipR Member

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    By the way each trans took 3.25 gallons. 6.5 gal total.
  14. CSkipR

    CSkipR Member

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    For those that asked I took the boat out this weekend to for a couple of runs. Didn't notice any difference in the way the transmissions operated from the previous 5-40w oil to the new 40w oil. Over more time will see if the port trans still leaks a little oil (teaspoon all day). Didn't appear to after these runs but more running time will tell.
  15. Beau

    Beau Senior Member

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    Great. Is the leak new?
  16. CSkipR

    CSkipR Member

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    No its been a very small and slow leak for a few years. May have been because of the lighter weight oil.