What Causes a Thud Noise When Taking Foot Off Gas Pedal
Let’s look at the common problems that cause a clunk or thud noise when taking the foot off the accelerator pedal.
Symptoms
- Car thuds when letting off-gas
- Noise when taking the foot off the accelerator
- Clunk noise when letting off the gas pedal
- Knock sound when letting off-gas
Common Causes
Worn mounts, suspension, and steering problems can cause a knocking noise when taking the foot off the accelerator pedal.
Let’s take a look at some of the most common problems.
Differential Mount
A bad front differential bushing caused these symptoms. The bushing shown in the picture will crack and create too much free play for the differential. To verify, jack up the car. Grab the end of the front differential (carrier) and check for play.
If there is any play or cracks, the rubber bushings should be replaced.
Also, visually inspect the rest of the front differential bushings for cracks. There are three bushings. 
The rearmost bushing seems to fail most often.
Engine or Transmission Mount
Another common issue that causes similar symptoms is a broken engine or transmission mount.
Control Arm Bushing
A worn control arm or thrust link bushing can cause a hit when accelerating or braking. It can be an indication of an extremely worn bushing.
Do not ignore a car that thuds when taking the foot off the accelerator pedal. Your vehicle may have a serious issue that needs to be repaired immediately or risk putting yourself and your passenger at risk.
Have an auto mechanic perform a vehicle inspection to determine why your car makes a knocking sound when letting off the gas pedal.
We hope you find the What Causes a Thud Noise When Taking Foot Off Gas Pedal guide helpful. Check these troubleshooting and repair guides for more help on your vehicle.
