Thanks for the replies. OK, makes more sense to me now about the breather plug. The breather plug in my gearbox does not have a brass element (sintered). It just has a small hole through one of the hex surfaces. Sounds like it’s doing its job as designed with the small leakage amount. But this was the first time I noticed a leak and that was the reason for my concern. I did tighten the breather plug so that the vent hole will now be facing downward. Seemed like the right thing to do. I’ve had my equipment going on 3 years now but I don’t put a lot of hours on implements or tractor. So I’m really still a rookie to owning this fascinating equipment.
As for the gear oil…I researched the spec sheet PDF on Schaeffer site. I can’t post links yet but see excerpt from their 3 page document……
Shaeffer 75w-90 Synthetic:
1. Enhanced thermal and oxidative stability and durability to handle operating temperatures of 300***61616;F to 350***61616;F.
2. Excellent extreme pressure properties to protect the gears and bearings from excessive wear and fatigue.
3. Prevention of the formation of sludge and carbon deposits that erode the seals.
4. Excellent seal compatibility.
5. Enhanced protection of copper, brass and bronze components from corrosion.
6. Non-corrosivity to brass, bronze and other non-ferrous metal parts.
7. Excellent protection of components from rust and corrosion in dry conditions and in the presence of moisture.
8. Excellent resistance to water and moisture.
9. Excellent water separability characteristics.
10. Enhanced gear, bearing and seal cleanliness
11. Excellent resistance to foaming.
As already pointed out by Dave it says excellent EP properties. So I guess that box is checked?
I had bought a quart of gear oil a while back from my Kubota dealer and told them my exact application. They also looked up my tiller in the system. They gave me Service Pro 80w 90 gear oil API GL-5. Not sure what those ending digits mean. The Service Pro bottle does not state AW nor EP. But I did get this from their spec sheet…..
SERVICE PRO® Premium GL-5 Gear Oils are compounded with highly refined base stocks and additives to ensure extreme pressure characteristics, anti-wear, corrosion inhibition, rust preventions, low pour point, and anti-foaming performance. They are fully formulated for limited slip differentials.
As far as the EP and meeting all the same vehicle/military specs, the products appear to have the same capabilities. However, both talk about EP & AW or protection from excessive wear. So I’m still a bit confused as to the EP vs AW. Thanks for the input.