Technical Panda 4x4 rear end knock

[Thingy]

Hi,

Got a strange issue with my 2012 Panda 1.3 diesel 4x4. After about 10 mins driving a knocking sound starts from rear end, the sound speeds up in time with wheel rotation. It happens on flat ground and in straight line. Jacked car up and could not replicate the sound by manually rotating wheels but the knocking can be produced by pushing the car when in neutral. Thought it might be a CV joint but no way of telling. As I said this only starts after first few miles driving. Any ideas gratefully received.

 

[Herts Hillhopper]

Is it perhaps from the rear diff? How’s the oil level in that?

 

[Thingy]

Will Check the diff oil but always assumed diffs made a whining noise rather than a knock.

 

[Panda IIs]

Backlash in the propshaft/drive line?

 

[R1NGA]

Could easily be the rubber bushing on the centre prop shaft bearing getting sloppy, introducing additional loads and wear on the bearing itself and making it knock. Will be road speed dependent and worse at some speeds than at others. I have this slightly on mine already (2014 4x4 TA, 57,000 miles) and have a new prop shaft assembly on the garage floor waiting to fit, come the time...

 

[Thingy]

Thanks for the suggestions about the propshaft. The part that confuses me is that the knocking only starts after driving a few miles and also if I stop, switch off the engine, put it in neutral and push the car the knocking is still there i.e it is knocking with no drive through the gearbox and no load - but again only after being warmed up.

 

[Herts Hillhopper]

This was to be my next suggestion (the failing support bush). Pushing the car in neutral will still turn the prop shaft (because of ‘stiction’ in the front diff to prop shaft drive)