Frame Conditions. GMC Truck GMC P42 Commercial Chassis 1998

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC P42 Commercial Chassis 🢒 Body and Accessories 🢒 Frame and Underbody 🢒 Frame Conditions

Table 1:	Sag
Table 2:	Buckle
Table 3:	Sidesway
Table 4:	Diamond
Table 5:	Twist
Table 6:	Improper Tracking
Table 7:	Cracks in the Web of the Rails

Sag

Problem

Action

The load is greater than the frame is designed to carry.

Straighten and reinforce the frame. Refer to Frame Repair .

The load being carried is uneven.

Straighten and reinforce the frame. Refer to Frame Repair .

The vehicle has improper body or accessory mounting, such as the following examples:

•	Holes are drilled in the flange of the frame rail.

•	Too many holes are in the web section of the rail.

•	Holes are in the web section which are too close to each other.

•	Four or more holes are in the same vertical line of the rail web.

•	Welds are on the flange, particularly across the flange or along the edge.

•	Holes are cut in the rail with a torch.

•	Notches are cut anywhere on the rails.

Straighten and reinforce the frame. Refer to Frame Repair .

The vehicle has been in a fire.

Straighten and reinforce the frame. Refer to Frame Repair .

The vehicle has been in a collision.

Straighten and reinforce the frame. Refer to Frame Repair .

Equipment has been used that the frame has not been reinforced for.

Straighten and reinforce the frame. Refer to Frame Repair .

Buckle

Problem

Action

The vehicle has been in a fire.

Straighten and reinforce the frame. Refer to Frame Repair .

The vehicle has been in a collision.

Straighten and reinforce the frame. Refer to Frame Repair .

Equipment that the frame has not been reinforced for has been used.

Straighten and reinforce the frame. Refer to Frame Repair .

In addition to these causes, refer to the following possible causes under Sag:

•	Abrupt changes in the section modulus

•	Improper body or accessory mounting

Straighten and reinforce the frame. Refer to Frame Repair .

Sidesway

Problem

Action

The vehicle has been in a fire.

Straighten and reinforce the frame. Refer to Frame Repair .

The vehicle has been in a collision.

Straighten and reinforce the frame. Refer to Frame Repair .

Equipment that the frame has not been reinforced for has been used.

Straighten and reinforce the frame. Refer to Frame Repair .

In addition to these causes, refer to the following possible causes under Sag:

•	Abrupt changes in the section modulus

•	Improper body or accessory mounting

Straighten and reinforce the frame. Refer to Frame Repair .

Diamond

Problem	Action
The vehicle has been in a collision.	Straighten and reinforce the frame. Refer to Frame Repair .
The vehicle has been towing another vehicle with a chain attached to 1 corner of the frame.	Straighten and reinforce the frame. Refer to Frame Repair .

Twist

Problem	Action
The vehicle has been in a collision.	Straighten and reinforce the frame. Refer to Frame Repair .
The vehicle has been operating in very rough terrain.	Straighten and reinforce the frame. Refer to Frame Repair .

Improper Tracking

Problem	Action
The vehicle frame is out of alignment.	Straighten and reinforce the frame. Refer to Frame Repair .
The front or rear axle has shifted.	Realign the axle. Secure the axle.
The vehicle has incorrect wheel alignment.	Align the wheels. Refer to Wheel Alignment.

Cracks in the Web of the Rails

Problem	Action
The crossmember attaching bolts are loose.	Weld and reinforce the rail. Replace the rail, if needed. Ream the bolt holes. Replace the bolts with larger bolts, if needed. Retighten the bolts.
There is a concentration of stress that may result from many different factors. Refer to Minimizing Frame Service Description .	Weld and reinforce the rail. Replace the rail, if needed.