Gear oil leak - Alpha one gen 2 drive

[KHE]

I noticed a spot of oil on my driveway under the bell housing. When I inspected the area, it was collecting on the speedometer tubing and dripping to the ground. I can see it leaking from the upper shift shaft on the upper half of the drive. I don't see a seal on the Mercruiser parts diagram but am obviously missing something.

It's possible it is coming from another area - I need to inspect it in closer detail.

 

[atrick]

Shift shaft or input shaft seal, just did both on mine this year, need to get drive pressure tested to be sure.

 

[KHE]

It's not coming from the lower (drive side) but it is coming from the upper shaft.

 

[Bt Doctur]

shift into fwd and pull the drive for inspection #20 are 2 seals
click to enlarge

 

[KHE]

The leak is coming from the lower portion of the keyhole area - not the large bore where the u-joints and yoke pass through - the lower portion. I didn't think any gear oil was present in that area. I wonder if it is the check valve where the oil passage leads to the drive is somehow leaking into the lower area and then a seal is leaking at that point?

Funny thing is it has been sitting for two days and it is bone dry - no oil residue whatsoever.

 

[KHE]

Shift shaft or input shaft seal, just did both on mine this year, need to get drive pressure tested to be sure.

I'm preparing to begin to work on this as soon as I bring the boat home from storage in two weeks. Is your thought the oil is coming from the area behind the U-joints and leaking into the bellows area, then leaking through the shift shaft seal onto the zinc anode?

If the shift shaft seal were bad, there would be water in the u-joint bellows which there is not - it is dry.

When i pulled the drive last fall, there was a lot of oil around the check valve which I attributed to be from working the drive off the bell housing.

 

[atrick]

The oil leaked into the bellows and then was getting past bellows into water. The bellows was due for replacement but had a lotof oil in bellows with just a little bit of water. Water never got into drive as I ran it for 2 months before pullout that winter. I figured the pressure difference between the 3 places kept water out.

 

[Bt Doctur]

to have oil in the bellows your drive res should have been getting low.That oil is from a leaking inputshaft seal. If the bellow was dry, suspect the oil hose from transom to gimbal

 

[KHE]

Bt Doctor and all,

I drained the gear oil from the outdrive a couple of days ago and there was no water in the oil. I am going to pressure test the drive but the local WestMarine store didn't have a fitting in stock. I'm wondering if that is really necessary since there wasn't any water in the gear oil.

I replaced the oil line almost four years ago - the original was cracked. Since the boat is in the driveway now, I can inspect it again just to rule it out. The leak is not enough to show up in the reservoir.

Is there any way to test the shift shaft seal other than replacing it? I hate to throw parts at a problem. In the case of the shift shaft seal, the set screw is a bugger to remove and the mating part is usually destroyed in the process from what I have read. I'd like to avoid that if possible.