TM 10-3930-659-10 2-9.  OPERATE DRIVER’S SEAT (Con’t) (2) Turn lumbar curvature and vertical adjustment  knob  (13)  counterclockwise  to lower lumbar support and clockwise to raise lumbar support. (3) Adjust   backrest   cushion   (11)   tilt   by   lifting backrest    cushion    tilt    adjustment    release lever  (7)  and  moving  backrest  cushion  to desired angle. (4) Adjust backrest extension (12) height by pulling up or pushing down on backrest extension. d.  Armrest (8) adjustment. (1) Adjust tilt by turning armrest tilt adjustment knob (9) clockwise to increase tilt of armrest (8) and counterclockwise to decrease tilt of armrest. (2) Height of armrest (8) can also be adjusted.  If adjustment is required,  notify Unit Maintenance. TA704493 2-38