Whirring noise at 80kph

[Sammysam]

Hi, I have a problem with my manual 4x4 2013 SR Hilux and was wondering if anybody has had any similar problems or may know what the problem may be. When it gets up to 80kph it makes a whirring or humming noise. It continues up to 90kph but stops after that. Also stops when I depress the clutch. Makes a sound like it is winding down. Have had it at mechanics. At first they thought it was the spigot bearing/ clutch so put in a new clutch. Then put in new gearbox and the noise continues. At this stage they are not sure what it is. Has anybody had any similar issues or know what the problem may be? They are thinking maybe, center bearing or Diff but not sure.

[CONROD]

Can you try it in 4 wheel drive , on a straight road and see if you experience the same symptoms, also is it coming from the front or back. When its doing it at say, 85kph can you pop it in neutral then bring the revs back up to same speed and see if you can hear it again, might be a stuffed bearing in the Alternator, or power steering pump

[Bigpete]

Could remove the rear tailshaft ,Run on the front diff see how that goes

[DvsOne]

May sound dumb but have you checked your wheel bearings and also tyres?? Scalloped rear tyres can cause similar symptoms.

[Novicebutnice]

12 hours ago, DvsOne said:

May sound dumb but have you checked your wheel bearings and also tyres?? Scalloped rear tyres can cause similar symptoms.

Since the noise disappears when he puts his foot on the clutch, it rules both of those out.