I use the Amsoil severe gear in mine since my second oil change. No problems so far. I bought it new in 2012. I use the Redline Heavy Duty Shockproof in my track car. Transmission and diff. It's the only stuff that holds up under track use. I have never thought about trying it in my boat. I don't want to be the first one to try it. 96 hours so far on drive and motor. I use the Redline synthetic oil in the motor. I also use it in my car. It's probably overkill but why not.

The only problem you might run into with Shockproof Heavy is that it foams.

I`ve yet to see any "foaming"

That's why I stated 'might' :)
I use it in HD transmissions, friends use it in #3 and Bravo drives with little foaming; I don't use it in my #6 or Bravo, I have a special cocktail I use there which I have discussed with Red-Line's chief chemist. Similar additive package just in a different base stock. I do miss the tackifier that Red Line has, really good stuff.

Glad it works in your application, it is an excellent product.

I've used Quicksilver, Redline Heavy 75-250 and Amsoil Marine 75-140?. None of them kept the teeth on a Bravo more than 100 hours. None of the drives had pitting so I'd say all the oils were basically good.

I remember reading somewhere on the interwebs (so it has to be true) that Teague was running 10W40 Motorcycle oil in his #6's on the Amsoil boat. You guys are going in the wrong direction! :p

Knot. That is correct. Teague has used the Amsoil MCF 10w40 for years in his 6's. It has a GL-1 gearlube additive built into for cycle transmission applications. This boat as well, http://www.powerboatlistings.com/view/37485, up until it was sold to the current owner, also ran the MCF 10w40 in his Bravo X's for 3 years with ZERO WEAR on the gears.