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We have just purchased a 2004 Nissan Vanette VX, auto travelled 70k.

It has an annoying differential whine starting from about 70kph and disappearing at around 95kph. The whine disappears instantly when lifting the throttle. I have changed the differential oil with little improvement.

Any suggestions?

Ian

From the "Ask Jack" archive - 19 September 2009

The whine sounds like the mating of the crown-wheel and pinion in the rear differential unit and may never let you down or cause any major mechanical problems.

To try and remove or reduce the whine however could become a very frustrating and expensive exercise. What can happen is the whine simply moves to a different road speed which may be acceptable to you or make the situation worse.

The first step would be to take the vehicle into your local repairer for a test drive an opinion. Also get them to check the oil you have added is correct for this make and model.

This type of noise can be a nightmare to fix to be honest. Much work has gone into insulating the cabin of rear wheel drive vehicles over the years to try and quieten or hide such noises.

If you do decide to do something about it and a repairer can confirm the whine as a crown-wheel and pinion issue, then I would get a differential specialist involved in the repair. Be warned though, the whine may never totally disappear.