My experience with oil temperature is based on engine oil temps. At 200 degree F it is in a safe range for the oil and nondestructive for components such as rings, bearings and other moving components. I have successfullly run synthetic engine oil for extended periods of time at up to 300 degrees F in a V8 engine running road track events.
I am not suggesting that 300 degrees is a desirable temperature but I have not been sucessful in reducing this operating condition. In talking to engine builders they seem to accept this as the upper limit for reliability of operation.
My point is that if the bevel box is running at 200 degrees F then that seems to be in a very safe range and is not contributing to the noise problem.
