Alterations; Shear Plate Attachments; Trailer Towing - GMC GMT 610 Manual

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G/H V GMT 610
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Alterations

If the wheelbase is modified, the alterer must take responsibility for compliance with affected motor vehicle safety and emission
standards and for warranty on items such as driveshafts, universal joints, center bearings and rear transmission tailshaft, transfer case and
transmission case fractures, output shaft bushings, bearings, brakes, fuel systems and any other related component failures.
Additionally, the customer must be alerted in the modifier's owner's manual that parts for the reworked area are not available through the
General Motors Service Parts System.

Shear Plate Attachments

Attachments of shear plates should be accomplished by using existing manufacturing holes already available.
When additional holes are required for shear plate attachment, they should be no larger than 20 mm (0.75 in.) in diameter. Holes are to be
drilled no closer than 63.5 mm (2.5 in.) apart. For holes drilled forward of the rear axle, centers are to be no closer than 63.5 mm (2.5 in.) from
the top or bottom flanges and no closer than 89 mm (3.5 in.) from any suspension attachments. For frame holes drilled rearward of the rear
spring hanger bracket, hole centers are to be no closer than 51 mm (2.0 in.) from the top or bottom flange and no closer than 89 mm (3.5 in.)
from suspension attachments.
Required large holes such as 20 mm (75 in.) diameter or larger, should be kept to a minimum required opening. Tubes should be welded in
place if holes in excess of 25 mm (1.0 in.) diameter are required.

Trailer Towing

The Incomplete Vehicle Document specifies that the CG location be within certain limits. The Body Builder must use all appropriate data.
Note to Body Builder/Final Stage Manufacturer: Failure to keep body and payload CG at least 26 inches forward of centerline of rear axle
will result in degradation of trailer towing capacity. Consult the Trailer Towing Guide to determine maximum tongue load for your vehicle.
G/H Van (GMT 610) 2005