knocking then burning then fine????

[busdriver]

Hello
Had a strange problem today.
I was at work, jumped in my van to go shop and there was a real loud knocking noise coming from underneath asa I moved slowly forward and reversing.
Phoned mate, he said " take propshaft off and tighten nut on diff "
I done this and the nut wasnt fully tight. Tightened that and psoblem was exactly the same.
On the way home there was a sort of wooshing noise and then a real strong smell of rubber. I pulled over, looked underneath and everything ok. Knocking noise gone too.
Any one experienced similar or know what happened?
Olly

[FredTransit]

I haven't had this, but I am thinking that maybe the centre bearing (donut) might have been a bit off, and suddenly reseated itself. You know what they say, if it aint broke, don't fix it!

[busdriver]

hello fred
That could well be the case my friend. time will tell i suppose
Thanks for input
Olly

[busdriver]

Yes fred it was the center bearing ( donut ). The burning smell was the rubber burning away. all fixed now though. cheers