# Cracked Gear Case ‘01 Yamaha 40hp



## JRyno10 (Feb 3, 2014)

Long story short, gear case oil leaked all over my driveway. Boat was already scheduled for annual maintenance so I had them inspect that too. I assumed my prop shaft seal had gone out. Apparently I have a cracked gear case. I do not recall hitting anything. I also had recently changed the gear case oil. I have not seen the crack but will go down there Monday to see it. Not sure where to go from here. I was told it would require a new one and it would cost $1700. What are my options if any? Does this sound like an accurate price?
Thanks,


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## Smackdaddy53 (Dec 31, 2012)

It could just be the prop shaft seals.


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## lemaymiami (Feb 9, 2007)

If you have a cracked gear case it will be easy to see - when the shop shows you where it's cracked (an internal crack will breach any seal, but won't be visible until the gears, shaft, etc are removed..) -- and generally will require a replacement. Here you do have some options (but none of them as good as a new case - no matter how much it costs..). First you can try to find a used lower unit for a direct replacement (and if the unit is in good shape you'll get good service... but that's also the downside since you have no way to know how it was used... or how hard...). Next is a used case that needs to be re-built (with your internals) and with the same downside... 

Lastly you need to take a hard look at your existing motor - is it worth the expense of the new lower unit casing? It might be time to re-power - but that's your decision and good luck either way you go. Post up how it comes out for you.


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## mwolaver (Feb 6, 2014)

Back in the day, I had a yamaha 90 that suffered a cracked lower unit. In my opinion, this was a design defect, not impact. The prop shaft seals were in a trunion or carrier that was held in with a reverse threaded spanner. Those threads were a perfect hideout for salt and eventually corrosion...building up to the point of cracking the gear case in that "bell" area. I drill-stopped the crack and had it heliarc'd and it lasted for several years. So, I think, depending on the location of the crack and the skill of the welder, you could have it repaired and rebuilt. I think there are some experienced welders on here that can chime in.


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## andy race (Jan 15, 2018)

mwolaver said:


> Back in the day, I had a yamaha 90 that suffered a cracked lower unit. In my opinion, this was a design defect, not impact. The prop shaft seals were in a trunion or carrier that was held in with a reverse threaded spanner. Those threads were a perfect hideout for salt and eventually corrosion...building up to the point of cracking the gear case in that "bell" area. I drill-stopped the crack and had it heliarc'd and it lasted for several years. So, I think, depending on the location of the crack and the skill of the welder, you could have it repaired and rebuilt. I think there are some experienced welders on here that can chime in.


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## andy race (Jan 15, 2018)

SEI marine services sell's completely rebuilt lower units for about $1000.00 with a 2 or 3 year warranty, even if you hit something and break it they will replace it, I believe they are in Tampa and will ship for 50.00. I know someone who bought one , hit a rock and they did replaced it. Fish from homosassa to north of yankeetown so hitting stuff here is part of the game, I have never dealt with them directly and have not talked to this individual in a number of years, other's here may know more about them that may be negative. worth a call.


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## Smackdaddy53 (Dec 31, 2012)

andy race said:


> SEI marine services sell's completely rebuilt lower units for about $1000.00 with a 2 or 3 year warranty, even if you hit something and break it they will replace it, I believe they are in Tampa and will ship for 50.00. I know someone who bought one , hit a rock and they did replaced it. Fish from homosassa to north of yankeetown so hitting stuff here is part of the game, I have never dealt with them directly and have not talked to this individual in a number of years, other's here may know more about them that may be negative. worth a call.


SEI does not sell rebuilt Yamaha lower units. I called about one for my 70 a few weeks ago. I had one on my Mercury 90 years ago.


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## JRyno10 (Feb 3, 2014)

Thank yal for all the responses. I do not think crack is the right word and it is not located anywhere that I would have expected. I do not believe this needs a total replacement but I could totally be wrong. Behind the prop, there is a part that I guess is supposed to protrude out, and a seal - seals against it. It apparently no longer protrudes out how it should. I do not know what the part is called but I don’t see why that specific part couldn’t just be replaced?


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## JRyno10 (Feb 3, 2014)

To me and this is just following the part diagram. I think this part in question is the #43 - Lower Casing Cap.


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## ek02 (May 8, 2012)

That lower casing cap holds the seals and bearings and on a saltwater motor can be extremely difficult to remove. You need a puller and probably some heat to get it off. The corrosion is usually at the rear. Not a DYI job unless you have a lot of time, tools, and patience. I've done two and they were both difficult.


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