TM 10-3930-659-20 7-16. TRANSMISSION OIL COOLER BACKFLUSH (Con't). 7. Remove  hydraulic  hose  (21)  and  preformed  packing  (20)  from  transmission  oil  sampling  valve  (17).    Discard preformed packing. 8. Install preformed packing (18) and plug (19) on transmission oil sampling valve (17). 9. Place hydraulic hose (21) In suitable container (22). WARNING Hydraulic  fluid  Is  under  pressure.    Contact  with  flow  of  hydraulic  fluid  may result in Injury to personnel. 10. Start  engine  (see  TM  10-3930-659-10)  and  run  until  suitable  container  (22)  is  full.    Stop  engine  (see  TM  10- 3930-659-10). 11. Remove  plug  (19)  and  preformed  packing  (18)  from  transmission  oil  sampling  valve  (17).    Discard  preformed packing. 12. Install new preformed packing (20) and hydraulic hose (21) on transmission oil sampling valve (17). TA707356 7-52