Alpha outdrive upper oil seal replacement

Lower unit drive shaft fits in

Lower unit drive shaft fits in a gear in the upper unit with an O ring on the shaft and a neopreme like seal that has a spring in it just below the gear that the lower unit drive shaft goes into. That neopreme seal and spring jumped out when I was reassembling the unit. I took it to a shop and he told me that grease on the shaft spline and staying out of salt water would save tearing into the upper unit and replacing that seal. His argument was that the seal simply keeps the grease that is on the shaft and recipient gear in place and those do not wear but simply provide a fit together so the seal is not even found in most he tears down from this freshwater lake.
Need the seal or not?

"I went through the same thing

"I went through the same thing. Why don't you do what I did and just replace the seal! Why do you need to tear the upper apart? If the drive is split, you just pop the old one out from the bottom of the upper and drive a new seal in with a 1/2 inch socket thats big enough to use as a seal driver. Should take about 10 minuets. I agree with the mechanic, the seals you mention are there to hold the grease on the splines. I presure tested the upper and it held air, those seals did not come into play. My local mercruiser parts guy sold just the one seal I needed for this. I'm not an expert, Just my 2Cents
Chris"

"I Just realized my drive is a

"I Just realized my drive is a pre alpha, mabey yours is different, Good Luck
Chris"

"You have to get to from insid

"You have to get to from inside the upper unit.

You need the seal. It keeps the drive oil in and the water out.

The older pictures show 2 seals. When you order the replacement, you'll get one that is actually the two seals in one assembly."

"The older MR drive and the Al

"The older MR drive and the Alpha 1 should have the same seal system. I replaced the seal with the lower off simply using a couple of picks to remove old one and replaced it using a seal installer with an extra long handle. The seal is is about 7-8 inches inside the housing, hence the long handle. A socket and drive extension will work if you can get the seal started in by hand but very difficult lining up the seal properly with it just balanced on top of the socket. Hard to see up in there."