Fluid instead of grease?

[BP-Revo]

I pulled apart my G2R on a couple nights ago to check the tranny, and noticed all the grease had flung off the gears. I decided to pack it with a ton of grease, but then after turning it by hand there was just too much resistance for my liking. So, I was thinking, why not use fluid?

I'm using the E-Maxx transmission with the GorillaMaxx single speed kit, and it looks like it sealed pretty well. If not, a few small dabs of silicone sealant applied with a toothpick or cuetip would be plenty.

Also, I'm getting Mikes Hybrid Revo diffs soon, and those look like they'd be sealable easily. So I thought of using a little bit of motorcycle transmission oil in there for lubrication. It would always collect at the bottom and the lower gear would pick it up and throw it around, so all the gears would stay pretty lubricated, and there wouldn't be much resistance at all (especially once the gears were spooled and the fluid was sloshing around).

Any thoughts to why this wouldn't work (except leaking out, thats an obvious concern and one I think won't be a huge problem).