Insufficient lubrication is the most common cause of noise and wear. It consists of a rigid half mounted on the compressor shaft and aflexible half, made up of a hub and sleeve, mounted on the fan drive shaft. The sleeve and hub are connected through teeth allowing the transmittal of power from one hub to the other. Crater Compound No. 1 or equivalent is normally added every 10,000 miles or monthly through a lubricating hole in the sleeve portion. If, however, noise is detected from the coupling with the engine running the conditions should be reported and corrected at the first opportunity.
Insufficient lubrication is the most common cause of noise and wear.
To apply lubricant the engine must be run long enough to warm coupling. Position one oil plug 45 degs off top vertical center and remove both plugs. Add warm lubricant until it starts to flow out of bottom hole then replug both oil holes.