As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE IN "AUTO" RADAR DISPLAY ALL RED IN FRONT OF A/C IN CLEAR CONDITIONS. LOUD MOTOR SOUND AND VIBRATIONS FELT AT THE SAME TIME. SHORTLY AFTER WXR FAIL FLAG ILLUMINATED. AFTER ABOUT 20 SECONDS - EVERYTHING RETURNED TO NORMAL. GROUNDED - YES. REMOVED AND REPLACED WX RADAR DRIVE UNIT PER B737-800 AMM 34-43-11, OPS CHECK GOOD. PERFORMED GROUND TEST PER AMM 34-43-00-710-802-001, TEST GOOD.