129 589 00 91 12 Stop plug - WS27.00-P-0140-12B

FG 27/Set B 

TRANSMISSION 722.9 

Use: 

Stop plug for sealing oil lines at automatic transmission and oil cooler.

Fig 1: Identifying Stop Plug (129 589 00 91 12)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.