TM 10-3930-66934 15-11.  SIDE SHIFT CYLINDER REPLACEMENT/REPAIR (CONT). NOTE Backup seals may come off during the step. (9) Push head (41) into the side shift cylinder (20) until shear ring (42) is exposed. (10) Remove shear ring (42) from inside of side shift cylinder (20).  Discard shear ring. CAUTION ’ Keep piston rod straight and concentric in cylinder.  Do not allow piston rod to become wedged in cylinder or damage to cylinder or piston rod may occur. (11) Remove shear ring (43) backup seal (44), preformed packing (45), head (41), and piston rod (37) from side shift cylinder (20).  Discard preformed packing and backup seal. NOTE If the left head of the shift cylinder is to be removed repeat Steps (1 through 7), if not go on to step (8). (12) Remove side shift cylinder (20) from chain vise. CAUTION Do not damage piston rod surface.  Cylinder will leak if piston rod surface is damaged. NOTE Note  location  and  position  of  preformed  packing,  gasket,  backup  seal,  and  wiper  rod  prior  to removal. (13) Remove gasket (46), preformed packing (47) from piston rod (37).  Discard gasket and preformed packing. 15-80