Gear box oil change interval?

[Irish Rover]

The recommended gear oil change interval on my boat is every 250 hours which is the same as the engine oil interval. I've just completed 250 hours in the 5 months since I bought the boat. The engine oil looks black when I dip it, and has undoubtedly lost some of its mojo, but the gear oil looks like new. Do others change the gear oil as often as the engine oil?

 

[Roberto]

I change the reduction gear oil (ATF) when it begins to shows black floating particles, which may be after 200 or 500 hours, depending upon usage.
Engine oil every 100 hours, but being a leaking Perkins 4108 oil replacement is basically continuous

 

[Refueler]

Posts like this make me feel guilty ... I'm terrible ... I literally change oil if I remember ! I think my PRM last oil change was about 3 or 4 yrs ago ... engine ? Blimey - cannot remember !! That's my SR25..... Perkins 4-107 + PRM

The Conq38 will get oil change in spring just after launch - so I can get oil warmed up to suck out. Yanmar 2GM20

My Primor MoBo - will get oil change similarly ... VP AQ170 6cyl

 

[geem]

Recommended oil changes on my engine are 500 hours or 1 year. Gearbox is 250 hours. I change the gearbox oil every 250 hours which is about every 2 years. When we are in the warm Caribbean, I only change the engine oil every two years as we don't motor much. This works out at about 250 hours. So, in reality, my gearbox oil is dictating my oil change routine. I do the lot every two years. I use the highest quality oil recommended. Gearbox and engine take the same oil. The gearbox oil always look pretty clean

 

[PeterBoater]

The recommended gear oil change interval on my boat is every 250 hours which is the same as the engine oil interval. I've just completed 250 hours in the 5 months since I bought the boat. The engine oil looks black when I dip it, and has undoubtedly lost some of its mojo, but the gear oil looks like new. Do others change the gear oil as often as the engine oil?

Gearbox oil won't look black because there is no combustion process, unlike engine oil. Gearbox oil will contain metal particles etc that won't change its colour but will require it to be changed as per the manual. Same for the filter if there is one.

 

[capnsensible]

Yeah, I've always followed the advice of the people who make them.....

 

[vyv_cox]

Engine oil contains small loadings of boundary lubricant such as ZDTP to lubricate contacts that do not generate hydrodynamic lubrication, such as piston rings and cams & tappets. This content is sufficient for lightly loaded gears that also do not generate hydrodynamic lubrication, but it is consumed over time.

Best to stick to the recommended change intervals.

 

[Blue Seas]

As PeterBoater says above, there is no combustion process in the gearbox hence no build up of carbonaceous material in the oil - but gearbox oil is subject to extreme pressures at the tips of the gear teeth when they mesh/unmesh (think how few teeth are in contact at any one time) and that pressure (and the associated shear force) has to be resisted by the oil to prevent very expensive damage. The MOD designation for gearbox oil was 'OEP 69' or similar with the OEP bit meaning 'OIL-Extreme Pressure' - it's a false economy to neglect it. Colour is virtually irrelevant.

 

[jac]

I do them at the same time. Fortunately i have Volvo saildrive and manufacturer say to use the same oil so i do

 

[Roberto]

I change the reduction gear oil (ATF) when it begins to shows black floating particles, which may be after 200 or 500 hours, depending upon usage.

Just to clarify, I have never seen red ATF becoming black like engine oil, but definitely remaining transparent red and incorporating black particles, similar to ground pepper. Once it was mainly because of having operated the engine quite a long time under a heavily loaded propeller, otherwise regular checks at about 100h intervals usually do not show any change in oil appearance.