Tracy,

I've installed a 5 mm thick IKO AZK35535 bearing replacing the 2mm thrust bearing stack along with spring loaded pins to preload the bearing and stop the plate side thrust washer rotation during torque reversal.  The photo shows one of the pins as well as the cupped middle thrust washer stack that was abandoned.

This seems OK on the test stand but has yet to fly.

-5 degrees F this morning, but the frost makes a nice picture.  I don't know why some photos end up rotated.

Steve Boese