Radiators appear to be replaced around 100k as preventative or they start leaking due to small cracks? This is what Toyota Owners shows:
OIL AND FILTER - CHANGE, TIRES - ROTATE, CUSTOMER STATES, DIAGNOSIS OF TIRE PRESSURE
LIGHT MALFUNCTION, AIR FILTER ELEMENT - REPLACE, CABIN AIR FILTER (STANDARD POLLEN/
ELECTROSTATIC) - REPLACE, PERFORM ADVANCED VEHICLE DIAGNOSIS FOR CONCERN - FLUID
BY TRANSMISSION/OIL PAN, TPMS SENSOR, REPLACE AND PROGRAM(1), REMOVE AND
REPLACE REAR CRANK SEAL - INCLUDES REMOVAL AND INSTALLATION OF TRANSMISSION
AND FLEXPLA ~|~REMOVE AND REPLACE REAR CRANK SEAL - INCLUDES REMOVAL AND
INSTALLATION OF TRANSMISSION AND FLEXPLATE ~|~ ~|~154128 LEAKING REAR MAIN SEAL 800
REMOVED TRANSMISSION AND REPLACED REAR MAIN SEAL. RESEALED REAR MAIN SEAL
PLATE, REMOVE AND REPLACE REAR CRANK SEAL - INCLUDES REMOVAL AND INSTALLATION
OF TRANSMISSION AND FLEXPLA, REMOVE AND REPLENISH WS TRANSMISSION FLUID.
RECOMMENDED AT 60K (SEVERE/TOWING) 100K NORMAL USE ~|~ ~|~,CUSTOMER DECLINED
SERVICE, REMOVE AND REPLENISH WS TRANSMISSION FLUID. RECOMMENDED AT 60K
(SEVERE/TOWING) 100K NORMAL USE, WIPER BLADES - REPLACE FRONT AND REAR, NEGATIVE
BATTERY TERMINAL IS CRACKED C/A, DIAGNOSIS OF TIRE PRESSURE LIGHT MALFUNCTION
RMS seems to not be common, but does happen - more so on Tundras and not year dependent. Guessing they just did the crank seal while they had the trans off.
Current owner says there was oil in that area and the dealer recommended those specific seals be replaced. Misdiagnosed cam tower maybe? Valve covers? Owner says it has not leaked since the repair so....