Volvo VNL 780 Operator's Manual page 438

428 MAINTENANCE AND LUBRICATION
Note: For 630 and 670 vehicle models, the frame height must be measured. See F in
illustration. If F measures 266 mm (10-1/2 inches), subtract 17 mm (5/8-inch) from the
value determined for H.
VN Roof Extender Measurements
VN 630/670 Roof Extender
Adjustment Chart
W8003466
W8003472