Ken, you still need to narrow down what component has the problem. I could see no oil causing issues, but just being a little low seems like an unlikely cause.
Rob R. wrote:With the power off and the drive pawl flipped up, try spinning the fan coupler by hand...does it spin freely?
Have you gone through that exercise yet?
As for the oil, I was just discussing this with another EFM user this morning. A traditional gear lube is what I suggest, 75w90, 80w90, etc. The exact viscosity isn't critical since this is a low load and fairly steady temperature application, but you should pick a gearlube that meets/exceeds an API rating of GL4/GL5. If you can spare the extra $10 or so, a synthetic oil is a good idea.