Macwester gearbox

[2nd_apprentice]

how are you supposed to check oil levels on a marine gearbox? Not sure about the make, seems to be a ZF. No documentation whatsoever unfortunately. When we had a look yesterday the oil levels seemed to be alarmingly low and skipper decided to top up generously. This was without the eng9ne running. Now however with engine running and gearbox oil warm there seems to be plenty of oil in, well above the dip stick mark. Could this cause any harm? Skipper told me there used to be a breather but he'd blanked that off after filter element became obsolete. Engine's a BMC 1500 "captain" as fitted originally if that helps.

Cheers

 

[iowman]

Hi.
My macwester Seaforth originally had a BMC 1500 marinized by a company called JG Meakes, the gearbox was a PRM and had a small screw on oil filter. In about 1995 it was not possible to buy the oil filter and PRM advice was to replace with a plug. The box all so had an oil cooler on it.

Iowman.

 

[2nd_apprentice]

Thanks, that did help. PRM rang a bell with the skipper. Seems he's got the same setup as you had. Haven't been able to identify the model and all downloadable pdf files from prm are workshop rather than owner manuals. AIUI however you're supposed to check oil levels before starting the engine. This would probably indicate a leaking o-ring on our gearbox. We'll just keep topping up 'till home then.

 

[cimo]

........... however you're supposed to check oil levels before starting the engine. This would probably indicate a leaking o-ring on our gearbox. We'll just keep topping up 'till home then.

been there, done that.
From my own experience with ZF marinegears, proper procedure is to to open filler cap on gear box & wait a few minutes to allow pressure to equalise. Then dip.
Not allowing the box to equalise will result in a false low reading.
My understanding is it's not good to run ZF's will oil above the max. mark (- you'll have to drain some out).

 

[2nd_apprentice]

Well just read the FAQs:

Q: HOW DO I CHECK THE OIL LEVEL OF THE GEARBOX? A: To check the oil level, the dipstick must be fully screwed down and a level can then be taken. DO NOT over fill your gearboxes as this is detrimental to their performance. If a mechanical unit is overfilled, then this will cause the clutch to wear out and the performance will continue to deteriorate
-
...

Q: OIL IS LEAKING FROM MY GEARBOX. WHAT DO I DO? A: In most cases, this means that either a seal is damaged and needs replacing or there is a loose connection in your cooling circuit. It is best to call our Engineering department to discuss this problem.

Skipper's mechanic told him not to worry. Just keep topping up if necessary and he'll replace the seal in situ as soon as we're back home.