Transmission Oil Leak Repair

Here is my description of a DYI repair of a transmission oil leak that turned out to be the O ring instead of the oil seal. My boat is a 1989 IP35 hull #016. The seal, O ring and locking nut had been replaced 7 years earlier by a Yanmar mechanic for $1300. I did this without removing the transmission and I did it myself for the cost of parts ($33.43) in about 8 hours. Attached is a PDF file showing how I did this.

This is of immense help to me. I'm new to sailing & recently got a salvage IP35 that has the same leaks & need to fix.
By any chance is there dimensions info on the tool so i can make one?
Much appreciated.
Thank You

The tool my brother-in-law made out of an aluminum bar and some nuts & bolts is on the boat. I’m going there tomorrow and with take measurements for you.

BTW, it’s been 5 years and, knock on wood, no leaks!

HI Jim,

Fantastic guide! I would also be interested in the measurements for the tool if you have them?

Cheers,
Tom

10” long
1” wide
1/4” thick
1.5” between center of 2 mounted 1 1/2” x 1/4” bolts that extend 3/4” from bolt surface

Thank you very helpful! By the way That nut is rather pricey and it appears that there’s no issue to reuse it in case it helps someone.

Cheers!

Update from about 1500 miles down the road, make sure you use locktight and that you have enough metal left on the nut to caulk it. I did not and it came off in a rather extravagant way. As I went to replace it I noticed some serious wear on the output coupling (will have to be replaced unfortunately) and some wear on the output shaft. Changing that shaft requires a rebuild that I’m not convinced the transmission needs and/ costs a fair bit of money. I noticed that your shaft has a similar amount of wear Jim, maybe slightly less than mine, but it appears that you have gotten about 5years out of it so far. Any idea how many hours you’ve put on the engine since? Trying to decide if I should go down the full rebuild route or just replace the coupling/ nut / rear seals?