Thanks for all the suggestions, guys! We have finally come to the bottom of this. It was not the coupling, but rather the engine was gone. The injector was not working properly,the injector nozzles were kind of blocked and the head gasket had to be replaced. It was purely a matter of an engine about to pack up. Now that all these have been sorted out, it runs again like a dream!
I agree - this must be coupling disc.
You need 3512322100 (p/n)
As Michel says, sounds like the drive coupling between the engine and drive pump has gone and is more than likely just gripping & slipping, that's why you have some drive and burning rubber.
hef one look for conexion engine pomp