92 Terrano TD27t noise (can't figure it out)

[prado_boon]

Hi guys, thought I'd ask as there's loads of people with TD27's here...

Recently a mate's Terrano has started a whining noise that changes with RPM - it's at it worse @ 2.5 - 3.5k RPM.
It's auto.
It's noticeable a lot more when it's cold.
It's louder when you're accelerating under load in gear (so really have to be driving to hear it properly). Although it's still there in park "free revving" it...

Have had a good listen around with a stethoscope but it's really hard to hear where it's coming from.

Replaced:
Alternator.
Idler tension pulley bearing.
Checked viscous fan isn't hitting anything. (spins ok)

Some other people's suggestions where anything from Water pump to Input shaft bearing on the auto.

Could it be:
Viscous fan clutch (I wouldn't have though they make a noise when gone bad as it's a fluid coupling?)
PS pump ?
Water pump ? (looks ok, tight etc)
AC pump ? (doesn't change noise when turning on or off...)
Just the belts ? (they look fine...)

What suggestions/tip do you guys have?
Cheers

[lax2wlg]

I know a TD27 guy who had similar symptoms and it ended up being that the turbo was kafuzzled. To isolate remove hose to engine intake, run engine and replicate conditions, see if the noise calms down.

[prado_boon]

How will that stop the turbo from spinning?

[lax2wlg]

You're right, though in this case it calmed the noise down a bit which was enough to narrow down the source of the noise.

[prado_boon]

Whining noise still there. Might be coming from gearbox area.

What tests can we do to isolate if it's something in the gearbox ? (I'm suspecting maybe a input shaft bearing?)

Also could it be a spun mains bearing in the motor ? (what do they sound like when they're toast?)

Torque convertor ? (Do they make noise when bad?)

[prado_boon]

Update. Turned out the transmission filter was blocked and the trans lost pressure.
New filter, new fluid. Noise gone. Hopefully no long term damage!