| Author |
Message |
    
joe plakosh
New member
Username: magv10
Post Number: 1
Registered: 06-2006
| | Posted on Monday, October 12, 2009 - 09:12 pm: | 
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I have a 2000 twin engine boat powered with VP 5.7 gsi volvo penta duo-prop drives. I drained both lower units and I found one lower unit gear lube almost black in color and the other one golden in color. I use nothing but vp synthetic gear lube in both. I changed it last fall myself. what would cause the color to get that dark? this drive also has a slight noise when in neutral only, that is not affected by any steering wheel movement. the noise will instantly stop as soon as you put it in foward or reverse. I will be taking this drive to a volvo penta repair shop ,but i would like to have any thoughts on this first, thanks Joe. |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 4270
Registered: 04-2006
| | Posted on Monday, October 12, 2009 - 09:22 pm: |
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'Black' gear oil is normally due to high temp.
In twin engine installation different colours in the gear oil is quite normal, but yours seems a bit extreme.
Quite often the reason is that one engine is carrying the heavier load, the other 'trailing' at a lighter load.
It may not be a drive problem, but an engine/tach synch problem. |
El Pescador
Senior Member
Username: el_pescador
Post Number: 4989
Registered: 02-2006
| | Posted on Monday, October 12, 2009 - 09:25 pm: |
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Dark oil is usually caused by heat. Heat can be caused by applying too much power to the outdrive, or a slipping clutch, or a faulty bearing, or the oil not circulating, or....?
How many running hours does that oil have. Also, have you found any metal particles in the oil as well? |
joe plakosh
New member
Username: magv10
Post Number: 2
Registered: 06-2006
| | Posted on Monday, October 12, 2009 - 09:44 pm: |
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My tachs and snyc are right on. I am running a navman 5500 with fuel management system so i know both engines are running the same. I only have about 40-50 hours on the lube. I saved a little glass jar of each fluid to show the techs. I really think a gear or gears will be the culpret. thanks Joe. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 670
Registered: 03-2009
| | Posted on Monday, October 12, 2009 - 10:10 pm: |
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I'd have the oil tested for metallic residue. When you change the oil next time, and after it has been sitting at rest, try to catch the very first few ounces by leaving the top vent closed.
Examine this with a magnet and/or white cloth.
These drives circulate oil... lower to upper/back down again. The culprit could be either.
You need to find the source before real damage occurs, IMO.
This may involve an examination of both upper and lower gear sets. |
Morten Ringvold
Senior Member
Username: haffiman37
Post Number: 4272
Registered: 04-2006
| | Posted on Monday, October 12, 2009 - 11:23 pm: |
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Note that running twin drives of this type, the upper gearset will only be cooled by 'oil-spray' while the lower will be totally in oil. You will never get them equal.
let the dealer strip the top unit and check the gears. |
Ricardo E.
Advanced Member
Username: ricardomarine_vp
Post Number: 671
Registered: 03-2009
| | Posted on Monday, October 12, 2009 - 11:34 pm: |
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Volvo specifically designed the lower unit in a way that pumps the cooler oil from the lower to the upper..... and for this very reason... Cooling!
I beg to differ with the usage of "oil spray" for the upper gear set lubrication. There is an extremely sufficient amount of lubrication taking place within the transmission on these so long as the oil level is correct to begin with, IMO. |
