Transmission oil change solution found-Updated

We all recognize that having an oil drain hose installed on your diesel is one of the seven wonders of the sailing world. To change your oil as simply as hooking up your vacuum pump to the hose connected to the oil pan is a thing of immense elegance and time savings. Aeolus has this arrangement, and I am repeatedly grateful for it. Our previous boat, an Ericson, did not have this, and so I had to insert the little hose down the dipstick hole and hope for the best with reaching the bottom.

MG 360 with dipstick hole as intended oil drain access

It is not merely the time savings and ease of operation that these oil drain hoses afford that makes them so valuable, but the mechanic in me is well aware of the benefits of sucking the dirty oil from the bottom of the pan, thereby sucking out the metal shavings that are a part of engine wear and tear and that further contribute towards engine problems.

So what about our marine transmissions! I changed the oil in my old Hurth tranny at least once a year, and it involved sticking a small diameter hose down the fill hole and hoping for the best that I was reaching the bottom and getting all the old oil and shavings out. So with my new transmission, a Twin Disc MG 360, I thought about finding a way to install an oil drain hose just like with the diesel.

Turns out, not so easy.



The oil drain bolt on this Twin Disc is truly an odd size. It is an M10 bolt with a 1.0 pitch. This means it is metric, with a very fine pitch. Hard to find as a bolt, and it seemed absolutely no one made a hose barb with this thread pattern! There are some companies that make oil drain hoses, chiefly http://www.drainzit.com/ but they only carry hoses with a 1.25 pitch for use in Honda engines. I gave up, almost.

After a lot of looking, I ended up making my own device from an M10 bolt and a hose bar mated together with JB Weld. That was fun. But since I never really give up on a fun problem like this, I was able to find just what I was looking for!

My initial home made device

It so happens that Walbro fuel pumps use a hose barb that is M10 with a 1.0 pitch. I found it on a performance auto parts online store. You can just google the part number below. Like a needle in a haystack, I was amazed I finally found it. It came, and sure enough, it fits perfectly and is much smaller than the bulky device I had made myself.

Walbro part# 128-3014

So for anyone out there with a Twin Disc MG 360 transmission, this is the part to order if you want to install an oil drain hose system.

Installed on transmission. It will allow for hose attachment and have plenty of room to rise up along the hull to be pumped out with my vacuum.