* Suspension Component Issues: While you've replaced shocks, other suspension parts could be worn or damaged. This includes:
* Worn or damaged ball joints: These connect the control arms to the steering knuckles and allow for smooth articulation. Worn ball joints can cause a bouncing or wandering feeling.
* Worn or damaged tie rod ends: Similar to ball joints, these connect the steering rack to the wheels. Worn tie rod ends can lead to instability and bouncing.
* Worn bushings: Bushings are rubber components that cushion and isolate various suspension parts. Worn bushings allow excessive movement, leading to vibrations and bouncing.
* Worn leaf springs (if equipped): Leaf springs, common on heavier-duty trucks, can sag or break, causing instability and a rough ride. Look for cracks or excessive deflection.
* Steering linkage issues: Problems in the steering linkage can create feedback that feels like bouncing or hopping.
* Improper alignment: Even with new parts, an incorrect wheel alignment can drastically affect ride quality and cause bouncing.
* Tire Issues (despite being new):
* Incorrect tire pressure: Overinflation or underinflation can significantly affect ride comfort and handling. Check the pressure with a reliable gauge and inflate to the manufacturer's recommended pressure (found on a sticker inside the driver's side doorjamb or in your owner's manual).
* Tire balance: New tires can still be unbalanced. Improper balancing will cause vibrations and bouncing.
* Tire type mismatch: Ensure all four tires are the same type, size, and load rating.
* Other Factors:
* Load: Is the truck heavily loaded? A heavy load can exacerbate existing suspension problems.
* Body damage: Unseen frame or body damage from a previous accident could affect the suspension's geometry and performance.
Troubleshooting Steps:
1. Check tire pressure: Make sure tires are properly inflated.
2. Get a wheel alignment: Even new components can benefit from a professional alignment.
3. Inspect suspension components: Carefully examine all suspension components for wear, damage, or looseness. Look for cracks, leaks, or excessive play in the joints. You may need to take it to a mechanic for this step.
4. Check for body damage: Look for any signs of previous accidents that might have affected the frame or body.
5. Take it to a mechanic: If you're not comfortable inspecting the suspension yourself, a qualified mechanic can diagnose the problem accurately.
The bouncing at a specific speed (45 mph) suggests a resonance issue—something is vibrating at that frequency. A professional mechanic will have the expertise and equipment to pinpoint the exact cause. Don't continue driving with this problem as it could lead to further damage or even a dangerous situation.
