What was found
RECEIVED R REV UNLK CAUTION MESSAGE WHILE CLIMBING. COMPLIED WITH IAC AND QRH, MESSAGE REMAINED. RETURNED TO DAY. NO DRAG OBSERVED ON RIGHT ENGINE. OCCURRED AT 16,000 FT. VERIFIED TRS SELECTED TO "OFF". SELECTED EMER STOW PER QRH/IAC. AIRCRAFT REMOVED FROM SERVICE REF. 353570/3 FOR MEL. DEACTIVATED PER AWA SUP 15-046D, TR WAS FOUND IN STOWED POSITION, PDU ADJUSTMENT NOT NECESSARY. FOUND PDU DCV MEASUREMENTS OUT OF LIMITS. R/R RH PDU IAW AMM 78-32-03. OP'S TEST GOOD. REMOVED PLACARD AND REMOVED FROM MEL.