destroyed gears in upper gear housing.... Why??

[TBarCYa]

Last Monday I was out in the bay running around 30mph in my 1978 21' Regal with a Mercruiser 888 when suddenly there was a horrible noise from the drive and the engine stalled. The starter would not turn the engine but the drive turns left and right and trims up and down. When I got the boat out of the water and removed the drive (suspecting the u-joints were bad) I found that the input shaft for the drive would not turn. Good news for me because the engine was not damaged however when I took the cover off the 888 drive I found that there were teeth missing from both the drive and driven gears in the upper gear housing.

Now, I'm working on getting a rebuilt drive before next weekend but I'm wondering what would cause such extensive damage to happen so suddenly?? There was no noise from the drive prior to the destruction and it had run fine the entire day before this. The oil level is right where it should be and the oil looks metallic but not milky. I'm assuming that the oil was not metallic before the gears ate themselves but I really don't know since I've only had the boat for a couple weeks and had not gotten a chance to open it up.

If anyone could suggest to me why this may have happened so that I can prevent it with the new (to me) drive, that would be great.

Also, I was told that the Alpha drives will bolt up to my bellhousing without any problems but I'd like to see if I could get a second opinion on that one.

Thanks in advance for your help.

 

[WillyBWright]

Re: destroyed gears in upper gear housing.... Why??

Stick with an Alpha One, but yes they bolt-up. It's mixing Uppers and Lowers among the various generations of Alpha drives that gets sticky. But your lower should fit an Alpha One upper just fiine.

I just tore down an upper with a similar failure, only somehow the lube from the upper drive went away. The lower is fine and so are the bearings in the upper, even have lube still on them. But the gears stripped. They say they were in deep water at the time which should mean smooth sailing, but sometimes logs can lurk below the surface unseen. However in their case I believe it was from a previous strike that partially fractured one or two teeth which took time to fail. Had the drive failed due to lack of lubrication, the gears would've discolored badly and the bearings often sieze first. Their stripped gears were shiny silver and the bearings are only slightly discolored. My guess is that yours failed due to a similar fate.

 

[TBarCYa]

Re: destroyed gears in upper gear housing.... Why??

Definitely good news about the Alpha. Chances are tho, that I will be replacing both the upper and lower since on my drive (I know not all of the old ones are like this) the upper and lower share oil and I am worried about metal contamination in the lower unit. Eventually, I will rebuild both myself but for now I would like to get the boat back in the water as soon as possible.

I know that mine is not from lack of lubrication but I was certainly not in deep water when it happened. The fishfinder said 3' of water (2' below the prop) but you never know. It definitely didn't feel like it hit anything tho and there's no damage to the exterior of the lower unit so perhaps it was from a previous strike as you mentioned. I just wish I had a really early 888 with separate oil for the upper and lower so I didn't have to worry about tearing apart the lower unit. I've worked on cars my whole life but I've never opened up a marine drive before.

 

[Laddies]

Re: destroyed gears in upper gear housing.... Why??

Make sure you find the right gear ratio unit for your 888 before purchace

 

[TBarCYa]

Re: destroyed gears in upper gear housing.... Why??

The Seloc manual makes it seem like all of the 888 drives (302ci Ford v8s) use a 1.5:1 ratio. Other than counting teeth (since I cannot turn the input shaft) is there another way to find the ratio of the drive?? I've seen pictures where the ratio is stamped on the outside of the case, but I don't think this is the case for mine.

Thank you.

 

[Purduebarry]

Re: destroyed gears in upper gear housing.... Why??

Are you sure the correct lubricant is in the drive. You mentioned you are new to the boat. Who did what to it before you bought it? Just because you see fluid does not insure it was the right kind?

 

[TBarCYa]

Re: destroyed gears in upper gear housing.... Why??

That's a very good point. I have no history for the boat prior to my purchasing it other than that it had been run several times this season. The oil smelled like gear oil and had a heavy viscosity not unlike an 80w90 or 80w140 that I'd use in the differentials of my trucks. Of course, there's no way to know for sure.

 

[Tail_Gunner]

Re: destroyed gears in upper gear housing.... Why??

Umm just had a little something like that occur with my stern, there was no question as to what happened, it was my oversight on not checking the oil.............:'(

Anyway's been there done that next time if my ignorance win's the day i alway's can go to this back up

http://www.stern-drive.com/gear-case-pages/Alpha-One-Upper.htm

Opp's speaking of oversight........:devil:

 

[Bt Doctur]

Re: destroyed gears in upper gear housing.... Why??

Other causes are :
previous prop strike
leaking oil from the drive
damaged seal from an overheat leaking oil
improper filling of the drive causing an air-lock
a rotating leak
yoke seal leaking oil into the boot or bilge

 

[TBarCYa]

Re: destroyed gears in upper gear housing.... Why??

Tail_Gunner, I'm glad you posted that link. That price is competitive with what I can find for a rebuilt at a local shop.

Bt Doctur, I would have to think that a prop strike would be the one that caused my issue because there was no loss of oil and no visable leaks. The gears were also not discolored as if they had overheated. I don't recall the prop hitting anything since I've had the boat, but I never know what the previous owner did.

 

[Bondo]

Re: destroyed gears in upper gear housing.... Why??

Another Thought on the Why,......

It's a 30 Year old drive,..... I'm Sure that Somebody has had their fingers Into it Before.......

If that Somebody Didn't Properly Set-Up the Gear Preloads,........

Well,....... If you find out Who,... You can tell them that they Didn't get it Right...............
There's posts here All the Time from fella's who Don't see a Need for all those Fancy Tools the Techs have........

 

[RubberFrog]

Re: destroyed gears in upper gear housing.... Why??

There's posts here All the Time from fella's who Don't see a Need for all those Fancy Tools the Techs have........

The Big Dummys!