Gear lube poured out of gimbal bellows (Alpha 1 Gen 2)

[BenchmarkMarine]

Hi,
I have a 1997 5.7l Mercruiser with an Alpha 1 Gen II outdrive. I pulled the outdrive last week for maintenance and had a large amount (1qt by rough estimate) of gear lube come flooding out of the gimbal bellows area. This seems wrong to me. I purchased the boat 2 years ago and this is the first time I've taken the upper unit out. Previously had only pulled the lower unit so that I could service the water pump.
I have read through this forum about possible causes for gear lube in the bellows. i've also read the nice 'oil leaks' writeup in the technical information section. I also pressure tested the outdrive to 10 psi as an assembled unit, thinking I would find a leak at the seal behind the u-joints. From reading multiple sources, it seems this is usually blamed. But actually the drive has been holding 10 psi for a few hours and a soapy spray did not show any leak in that area.
What I did see, however, was gear lube oozing down the shaft leading from the upper unit into the lower unit, where it is visible at the exhaust channel. I was expecting to see a larger leak since there was so much lube in the bellows, but I'm wondering if this could have built up to such a level over multiple years. The only path I see is up the shift shaft at the seal to the gimbal bell housing, and then across the shift lever into the bellows. Just wanting to confirm if this seems logical. If you get a chance to look at the pictures I uploaded, there is quite a bit of milkiness or light colored gunk at the shift lever area, but the oil within the bellows was just black with greenish tint like gear oil.
I should note that the boat has been parked in my garage for months and there was never any oil on the ground. The boat ran trouble-free on the water, though there was definitely signs of oil leak as the lube monitor jug would show loss of lube, and there were some slight signs of oil in the water if we idled. I have only used the boat on fresh water, though there are some signs that at some point in its prior life it had been in salty conditions.
Thanks.

 

[dubs283]

When pressure testing a drive you must first drain the oil and once pressure is applied simulate operation by rotating the input splined/u joint shaft clockwise (looking at the drive from fwd) and manually shift the drive f/n/r

10 psi is fine for a preliminary test but 15 psi for 10 minutes is spec.

No doubt you have a leak(s) somewhere and with that much lube in the u joint bellows it points to the yoke seal. Seeing lube at the lower driveshaft would indicate the lower seal(s) in the driveshaft housing are also suspect

It may be in your best interest to reseal the entire drive assy

 

[Scott Danforth]

U-joints rusted, took out seal

 

[BenchmarkMarine]

Thanks for the responses. I really appreciate them.
I had not mentioned that I had drained the gear lube in advance, overnight, and had rotated the u-joint shaft as well, so I suspect this seeping was residual that just didn't drain out. Having looked at it some more, I agree with your point about resealing the entire assembly since it has to come appart even for the two seals at the lower driveshaft. A little above my skill level as a DIY guy, but I will give it a try.

 

[Chris1956]

That is a common problem. Replace seal and yoke. If you need new ujoints, this is a good time for that as well.

 

[BenchmarkMarine]

Thanks all for the help. I took the yoke and seal out today. From the side that faces the u-joint, the seal did not show any visual signs of damage. However, the yolk has a significant groove in it. I'm guessing this is the cause of my leak? Not sure how this would happen while the seal looked good, but I don't know if the prior owner had a bigger problem before and changed only the seal. Interesting also, the forward face of the seal carrier (toward the gimbal) that mates to the forward ring had gritty crud between them. I'm not sure what to make of this since everything else seemed nicely lubed and clean. I've attached a few pics. My plan is to replace the yoke, the seal, and hopefully the seal carrier assembly if I can get the latter two pre-assembled.

 

[Chris1956]

It is pretty hard to see seal damage, however, the groove in the yoke is obvious, hence the leak.

 

[nola mike]

Rumor has it that you can drive a new seal farther down the shaft past the groove, though I haven't tried it. Guessing it could also be speedi sleeved.

 

[Scott06]

Thanks all for the help. I took the yoke and seal out today. From the side that faces the u-joint, the seal did not show any visual signs of damage. However, the yolk has a significant groove in it. I'm guessing this is the cause of my leak? Not sure how this would happen while the seal looked good, but I don't know if the prior owner had a bigger problem before and changed only the seal. Interesting also, the forward face of the seal carrier (toward the gimbal) that mates to the forward ring had gritty crud between them. I'm not sure what to make of this since everything else seemed nicely lubed and clean. I've attached a few pics. My plan is to replace the yoke, the seal, and hopefully the seal carrier assembly if I can get the latter two pre-assembled.

looks like some moisture has been in the ujoint bellows. any corrosion near the seal will kill the seal in short order

I would do the u joints while you are in there. If they have the internal clip MOOG 315G or equivalent will work

 

[BenchmarkMarine]

I wanted to report back that I got the outdrive back together today with the new seals and new short yoke. Pressure tested - no leaks. I won't know for sure how well it went until I run it a few times this Spring, but so far it all looks good. Thanks everyone for your advice.