How does only the upper drive blow its gears?

On the glastron in my sig, the drive was already split apart. I just now got the top off and found the upper gears completely blown to shreds. The upper bearing looks great so it couldn't have been from lubrication failure. Any clues how this happens so I can make sure it does not occur on the replacement drive.

Also the lower unit "feels" good by hand, I have no way to run it to be certain, but as a result of the upper failure, will metal shreds & particles be stuck in the lower unit now. Oil was out already so I could not look at it.

Re: How does only the upper drive blow its gears?

upper gears will be destroyed from a loss of lube regardless of bearing condition

Re: How does only the upper drive blow its gears?

dubs283 said:

upper gears will be destroyed from a loss of lube regardless of bearing condition

Click to expand...

Ayuh,... Agreed....
And there's No doubt filings in the lower...

Re: How does only the upper drive blow its gears?

Can I flush it, or must it be stripped down and washed?

Re: How does only the upper drive blow its gears?

Anyone? I was thinking of flushing with 50% ratio of lube and kero. Then observing the drained fluid for metal particles. If present then the lower should be stripped down???

Re: How does only the upper drive blow its gears?

I recently lost an upper gear set due to a seal leak, bot the upper and lower I had on that boat this time were from SEI, but the upper was under warranty and the lower was no longer under warranty. Their tech people told me to flush it with engine oil...

We're talking about relatively large pieces of hardened gear or bearing metal "floating around" to get stuck between currently undamaged surfaces. The party line from Bond-o and Don S on this is that flushing isn't going to do it. You're on thin ice / borrowed time if the lower isn't disassembled and thoroughly cleaned as well as inspected to ensure that nothing is damaged that will lead to a catastrophic failure in the near future.

Re: How does only the upper drive blow its gears?

I've always heard if you blow the upper gears the metal will be in the lower as well and to go ahead and replace the lower too. Because you don't know what damage has been done to the lower. You don't want to smoke out your new upper from a bad lower. Like I said.... just what I have read.

Re: How does only the upper drive blow its gears?

The only reason I challenge this topic is because the oil transfer hole is very small, so only the fine particles will go down. I could be wrong though.

I will not be reusing the lower anytime soon as I found a complete 1.65:1 unit to swap on. I just hate to trash it. I do not have the tools to disassemble.

Re: How does only the upper drive blow its gears?

I tried this years ago trust me there will be lots of stuff in the lower and you will be flushing forever,and still getting particles with each succeeding flush. Dissassemble it.

Re: How does only the upper drive blow its gears?

Fordiesel69 said:

Can I flush it, or must it be stripped down and washed?

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completely disassemble, clean and inspect all components, re-seal and pressure test