Here's a breakdown of why:
* Loud knocking during acceleration: This points towards internal component failure within the drivetrain. Things like worn bearings, broken gears, or a damaged differential are prime suspects.
* Car jolting: This reinforces the idea of a sudden interruption in power transfer. A seized or broken component is preventing smooth power delivery to the wheel.
* Locked offside wheel: This is the most critical clue. A manually locked wheel indicates a significant mechanical blockage preventing rotation. This strongly suggests a problem within the differential, half-shaft, or axle connected to that wheel.
Possible Causes:
* Differential failure: This is a highly probable cause. A broken or severely worn differential can cause a loud knocking, jolting, and a locked wheel. The differential is responsible for distributing power between the wheels, and a failure will severely restrict or completely prevent one wheel from turning.
* Half-shaft failure: A broken or severely damaged half-shaft (the drive shaft connecting the differential to the wheel) could also cause this.
* Axle failure: A broken axle would also prevent the wheel from turning and cause similar symptoms.
* Transmission problems: While less likely to directly cause a locked wheel, severe internal transmission problems *could* contribute to the jolting and knocking.
What NOT to do:
* Do not drive the car. Continuing to drive with this problem could cause further damage and potentially lead to a dangerous situation. The locked wheel could cause a loss of control.
What you SHOULD do:
* Have the car towed to a mechanic: This is not something you should attempt to fix yourself. A qualified mechanic needs to diagnose the problem properly. Attempting to drive or further diagnose the issue could cause further damage and potentially be unsafe.
* Describe the symptoms clearly to the mechanic: Be sure to mention the knocking, jolting, and the locked wheel specifically. This information is vital for proper diagnosis.
The repair will likely be significant, potentially involving replacement of the differential, half-shaft, axle, or possibly even more extensive transmission work. Get a professional diagnosis to determine the exact cause and the best course of action.
