High pitch vibration

I've had an unusual vibration type noise appear this morning, its a kinda high pitch vibration that only occurs between about 2550 & 2650 RPM both on acceleration and deceleration and between gear changes also at same RPM. I think I'm about due for a new clutch, so it may be related (thrust bearing maybe??), but would like other suggestions. Just a bit strange that its only at said RPM??? Hoping not turbo.....

Kinda hard to pick where its coming from but sounds at or around the forward of the gear shifter/firewall area. I might see if I can go for a run through an enclosed area tomorrow and have a listen again.

Does it happen at idle ?

Dave.

No, nothing at idle. But it does if I rev to that range in nuetral, so I don't think its box related. Starting to think either a bearing in the turbo, or a crack in the exhaust somewhere. Will be having a better look in the morning.

If I rev past that range it goes away again too.......

drive shaft center bearing???

I was thinking the part that got a crack on my transfer mount.

Clutch maybe.

Dave.

Thanks guys, I've just had a bit of a look under the bonnet and its sounding like either valve clearances or timing chain....... Due for its 100K service in 5K so its gunna have to go early I think. Any idea what I should be paying for a 100K service anyways?

100,000km's shouldn't be that dear, as its only oil and filter.

120,000km's is the next big one with diffs, gearbox, transfer oil changes.

I had my valve clearences checked at 160,000km's and they were fine.

Dave.

Thanks Dave, was thinking all fluids were at 100K.

I found the problem too. Got hold of a stethiscope, and found the problem in the best possible location.... idler pulley....... Don't know why I didn't think of that earlier, it was probably the most obvious. Picked up a new one from Repco and fitted, all good now. Did the drive belt and a cooling system flush at the same time.
I suppose the positive of it is that I've been over everything else in the engine bay and found no other problems!!
Took some pics while I was at it and will post up a "how to" when I get some more time. Might help out some of the less adventurous DIYers with a pretty simple job.

No worries, my rattle in my Nav cost me $35 to fix.

Dave.