311 Cdi Vibration

[alanred]

Hello,
My brother owns a 311 cdi, he does about 1000 mile a week, maybe more.
Just lately the van has developed quite a bad vibration, so bad that it snapped his exhaust and he's had to have it replaced.
The vibration starts at 1250 rpm, between 30 - 40 mph. If you dip the clutch whilst moving it still vibrates.
Today he got both rear wheels off the ground while his assistant (wife) revved the engine upto vibration speed, he checked (visually) the prop and it appears to be sound. He's checked both rear wheel bearings and there ok.
Today he's gone out and while still creeping forward slightly he put it in reverse, he said there was a "clunk" and after that there is no vibration.

Could any of you kind people offer any advice please.

Thank you.

 

[GEORGEROV]

I would check the engine/transmission mountings.

 

[alanred]

Thanks for the reply.
I had already considered the engine/transmission mountings, but the fact that it still vibrates even with the clutch depressed put me off that !
The loud clunk today whilst putting it in reverse does point toward transmission mountings though.

Much appreciated GEORGEROV.

 

[dava]

Dual mass flywheel.

 

[panason1c]

I would again check the prop' 'uj' joints for any play (there shouldnt be any)

 

[alanred]

Ok, after a much closer look it turned out to be the Prop Uj, looked like it had just failed, no apparent reason !
£180 later (second hand prop) job done, no more vibration.

Many thanks for the help, very much appreciated.

Thank you.