Does my GL-5 75W90 need to be official?

[kd4pbs]

Well, not necessarily "official" since I have no idea what "unofficial" gear lube would be, but now that it has been run in the water, I discovered I need to replace the prop seals on this summer project. I'd really like to refrain from paying the exorbitant price VP asks for their oil, so I am curious if something decent like Mobil 1 GL-5 75W90 is acceptable. I seem to remember reading on here someplace that VP just re-badges Mobil 1, but I cannot find that post and wanted to run this by the experts first.

 

[Horigan]

I’ve read that VP oil does better with water contamination and is better for shifting…

 

[Scott Danforth]

I use amsoil marine gear lube.

 

[Bondo]

Well, not necessarily "official" since I have no idea what "unofficial" gear lube would be, but now that it has been run in the water, I discovered I need to replace the prop seals on this summer project. I'd really like to refrain from paying the exorbitant price VP asks for their oil, so I am curious if something decent like Mobil 1 GL-5 75W90 is acceptable. I seem to remember reading on here someplace that VP just re-badges Mobil 1, but I cannot find that post and wanted to run this by the experts first.

Ayuh,....... That's what I use,... full-synoil......

 

[cyclops222]

Good seals and 75-90 has been fine since 1986 in 2 small Evinrudes.

 

[dypcdiver]

740 hours in my DP-SM outdrive using Mobil 1 without problems, it used to be a recommendation in the manual but not now, however Mobil 1 is almost the same price as Volvo Penta. I buy it in 25 Ltr drum as it also goes in my Landcruiser and Rav4's gear boxes and axles.

 

[BRICH1260]

I`ve been told that Mobil 1 has limited slip additives. I believe VP suggests non limited slip additives because of the cone clutch. I run Amsoil gear oil as it has water absorbing abilities.

 

[kd4pbs]

Never have been a fan of Amsoil anything after a friend put Amsoil gear lube in the rear end of a truck I sold him and it puked a pinion bearing after a few hundred miles. I used Mobil 1 in it for it's whole life up to that point (180K miles).
I did find the old post I remembered reading a while ago...

https://forums.iboats.com/threads/volvopenta-outdrive-lube-issue-settled-for-me.557271/

The stuff to get today appears to be called, "Mobil Delvac Synthetic Gear Oil 75W-90". It's less than half the price of the VP branded stuff.

If VP specified it, I'm sold. Thanks!