IMO the brand of oil isn't the issue, most are very good. As long as it's fairly thin (low viscosity). I run Amsoil synthetic chain case oil, which is great and expensive. ATF or hydraulic oil would probably work just fine.
The main problem is the little 6203 / 5203 / 3203 bearing fails due to thrust loads from the aluminum tunnel and track drive shaft mismatch. Some sleds have the problem and others don't. The track drive shaft should be in tension between the two main support bearings attached to the tunnel. When the track drive shaft is too long, it jams back into the DD and ruins the little radial bearing.
The 6203 bearing was never intended to take thrust loads. It's only real purpose is to center the planetary gears. The 5203 can take much more thrust load, and the SKF 3203 can take several times more thrust load (3203 has the same overall dimensions as the 5203, with better metallurgy, better internal dimensions and precision surface finish).