Hi,

I've got this great '86 250 TD with 235,000 on it.

It runs beatifully. No smoke, handles like new. Except there is a harmonic vibration at low revs - sort of a hum. It is absent at very low revs in each gear, gets very loud at what I would guess is about 2000, then goes away again above that. I replaced all three engine mounts thinking each time that would do it but the noise is unchanged.

I've just noticed that the nearside rear tyre goes bald way before the others and the tread wears sort of at an angle. Does this sound related to loud hum?

Also can you realign at rear wheel yourself or does it take really sophisticated gear?

Thanks for any thoughts!