TM 10-3930-669-34 13-2.  MAST ASSEMBLY REPLACEMENT/REPAIR (CONT). (22) Install cross head (38) on primary cylinder (40). (23) Install two primary chains (32) on rollers (39). (24) Install  two  chain  retainers  (37)  on  cross  head (38) with four lock washers (36) and screws (35). WARNING • Carriage  assembly  weighs  802  lbs  (364  kg).    Attach  lifting  device  prior  to  installation  to prevent possible injury to personnel. • All personnel must stand clear during lifting operations.  A swinging or shifting load may cause injury or death to personnel. (25) Using a lifting device, install carriage (34) on mast assembly (15). 13-22