Volvo MS2B Reverse Gear oil drain/change

[Marathon1150]

I am for the first time on this boat (Beneteau 35s5 with a Volvo Penta 2003) planning to change the oil in the reverse gear (Volvo MS2B). It does not seem to have a drain plug. Our other boat, has a Hurth transmission that does have a drain plug but it is inaccessible. So on that boat I use an oil pump to drain the transmission through the dipstick hole.

Will that work on the Volvo MS2B?

I have spent 2 hours searching for information on this item but other than some diagrams and shop manuals that do not show a drain, there is no advice regarding how to remove the oil from this transmission.

Any advice will be much appreciated.

[Marathon1150]

Just in case somebody else as inexperienced as I am with this transmission needs to know how to change the oil, here is what I learned today.

1. There is a drain on the transmission. Its on the side opposite of the dipstick and is very well placed to fully drain the transmission. But, on this boat getting a receptacle underneath it that could contain the oil would be impossible.

2. I pumped the oil out through the dipstick hole. That worked very well. The capacity specification is 0.81 litres and I put back 0.8 litres.

Refilling the case is a very slow process. The fill hole is gigantic but the compact and tightly meshed nature of the gears that fill it, only allows a trickle of oil to flow through them. Putting the new oil in took longer than taking taking the old oil out.