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A couple of days ago I was driving a 5-speed Manual RHD 2002 Mercedes W168 A-Class CDI 170 Elegance and the offside front CV joint broke. This left me stranded a few miles from home and I have to recover the vehicle.

Whilst at the roadside I noticed that with the engine running, the gearbox in gear and the clutch released, the offside driveshaft was rotating at engine speed. Obviously without any drive being transmitted, the vehicle remained stationary.

In this instance I was fairly close to home and recovery didn't take long. However, whilst at the roadside, I wondered if I'd been able to somehow jam the offside driveshaft to prevent it from turning easily, would a normal, open differential have transmitted drive to the other wheel? Clearly this would provide a strange driving experience as you'd only effectively have one wheel drive plus you'd be putting stresses far beyond the usual onto the nearside shaft and hub but would this have worked strictly on the basis of an emergency measure to limp the vehicle to the next village?

  • You could, but how does a diff work and what would happen to the speed of the other wheel?.... – Solar Mike Oct 25 '17 at 11:14
  • The other wheel isn’t connected to the driveshaft so I assume it would just freewheel like the rears? – Steve Matthews Oct 25 '17 at 11:28
  • you have 2 wheels normally connected to driveshafts, so which ones are you saying are disconnected now? – Solar Mike Oct 25 '17 at 11:33
  • The offside front is disconnected at the outer CV joint. – Steve Matthews Oct 25 '17 at 11:39
  • note the locked shaft has to support the same torque as the driven wbeel. I submit this would be about impossible to achieve as a roadside repair unless you carry around a cutting torch and welding equipment – agentp Oct 25 '17 at 11:39
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If you safely "lock" the broken driveshaft, then the other front wheel will rotate if you put it in gear, note this will be at 2 times the speed... I did this to drive a saw bench from a rear axle vehicle...

  • Why is it twice the speed? (Not doubting it, just asking) – Steve Matthews Oct 25 '17 at 11:39
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    Because of how a "standard" differential works and the gears inside the cage. – Solar Mike Oct 25 '17 at 11:47

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