Sag

1. The load is greater than the frame is designed to carry.
2. The load has an uneven distribution.
3. There are abrupt changes in the section modulus.
4. There is an improper body or accessory mounting:

•	There are holes drilled in the flange of the frame rail.

•	There are too many holes in the web section of the rail.

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

•	There are four or more holes on the same vertical line of the rail web.

•	There are welds on the flange, especially across or along the edge of the flange.

•	There are holes cut in the rail with a torch.

•	There are notches cut anywhere on the rails.

5. The vehicle has been in a fire.
6. The vehicle has been in a collision.
7. There has been use of equipment for which the frame was not designed or reinforced.

1-7. Straighten and reinforce the frame. Refer to Collision Repair (Straightening the Body) .

Buckle

1. You may be using equipment (such as a snow plow) for which the frame was not designed.
2. The vehicle was in a collision.
3. The vehicle was in a fire.
4. In addition to these possible causes, refer to causes 3 and 4 under "Sag."

1-4. Straighten and reinforce the frame. Refer to Collision Repair (Straightening the Body) .

Sidesway

1. The vehicle was in a collision.
2. The vehicle was in a fire.
3. You may be using equipment (such as a snow plow) for which the frame was not designed or reinforced.
4. In addition to these possible causes, refer to causes 3 and 4 under "Sag."

1-4. Straighten and reinforce the frame. Refer to Collision Repair (Straightening the Body) .

Diamond

1. The vehicle was in a collision.
2. The vehicle was towing another vehicle with a chain attached to one corner of the towing vehicle's frame.

1-2. Straighten and reinforce the frame. Refer to Collision Repair (Straightening the Body) .

Twist

1. The vehicle was in an accident or a collision.
2. Someone operated the vehicle on very rough terrain.

1-2. Straighten and reinforce the frame. Refer to Collision Repair (Straightening the Body) .

Improper Tracking

1. The frame is out of alignment.
2. The front or rear axle has shifted.
3. The wheels are aligned incorrectly.

1. Replace or weld and reinforce the rail. Ream the bolt holes and replace with larger bolts, if necessary. Retighten the bolts.
2. Replace or weld and reinforce the rail. See Refer to Collision Repair (Welding) .
3. Refer to Wheel Alignment Specifications in Wheel Alignment.

Cracks in the Web of the Rails

1. There are loose crossmember-attaching bolts.
2. Many different factors can cause a concentration of stress. (See "Sag" in this Diagnosis. Also, refer to Minimizing Frame Service .

1. Replace or weld and reinforce the rail. Ream bolt holes and replace with larger bolts, if necessary.
2. Replace or weld and reinforce the rail. Refer to Collision Repair (Cracks) .