Transmission Oil Leak after oil change

[Toots]

I changed the transmission oil on my 2010 R-29 with Yanmar 260BY engine. Took her out for a short test run and when i returned and inspected the trans, a significant amount of trans oil had leaked out. Only thing I can think of was that I may have incorrectly inserted the trans oil strainer backwards when i reinstalled it and/or the oil strainer plate may have leaked. There was no strainer plate gasket installed when I disassembled it, but the manual calls for a gasket. i did notice a slowness to respond to the throttle when I returned to the dock - I assume from the low oil level. Wonder if anyone has experienced a significant leak after changing trans oil.

 

[BB marine]

There was no strainer plate gasket installed when I disassembled it, but the manual calls for a gasket.

There should be a cover gasket. It is a thin gasket that may have fallen off when you removed the cover plate. There should have been in this order 3 bolts, cover plate, gasket, spring and screen filter. If the gasket is not present or damaged you could experience a significant leak. The gasket is designed to make up for any misalignment of the two sealing surfaces or any high spots from nicks or burrs.

i did notice a slowness to respond to the throttle when I returned to the dock - I assume from the low oil level.

This is a hydraulic gear. If the oil levels were low it could cause a reduction in pressure which would cause slow response and eventually no response.

 

[knotflying]

Yes, check for the gasket. It can be elusive. It is very thin and often sticks to the transmission. If it did not, it could have fallen off and you did not notice it. Also I am pretty sure the oil is a straight 30 weight oil. That is what was used in my Yanmar transmission.

 

[Toots]

Thanks to you both for the useful comments. I will try and locate the gasket and failing that, order a new one. Yes, I am using straight SAE 30 oil.