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Discussion Starter #1
Just got a secondhand 2014 Leaf with approx. 38000 miles on the clock and have noticed a droning/humming sound which I'm concerned may be indicative of a problem.

It sounds similar to the problem discussed here Reduction Gear and Final Drive [Archive] - Leaf Talk | Unofficial UK Nissan Leaf Owners Forum particularly where described in the gearbox replacement bill "low pitched droaning [sic] noise @ approx 60mph".

The noise keeps the same tone throughout the speed range and is audible (though subtle) from about 25mph onwards, but loudest at 61 to 63mph where it seems to become resonant and can be heard above the stereo.

So far the possible candidates for the cause I can see are:
  • Something tyre related.
  • Wheel bearing.
  • Reduction gear.
Can anyone shed any light on this problem? Many thanks.
 

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Sounds like the reduction gear from your description and the other information you linked to.

To check for a wheel bearing, jack up each corner of the car and spin the wheels by hand. A shot bearing may be noisy enough to hear. Does the sound change if you weave the car from side to side? If not, it may not be a wheel bearing.

What tyres are on the car? Are they old/worn? Are there steps in the tread or the rears worn on the inner or outer edges?
 

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Discussion Starter #3
Hey Tooks thanks for your quick reply!

From memory the sound doesn't change as I steer, though it might be slightly more noticeable when cornering, not sure.

The front tyres are pretty old I think - the rear ones were just replaced but not the front so they're definitely older. I will inspect the tread later.

Thanks again.
 

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Just got a secondhand 2014 Leaf with approx. 38000 miles on the clock and have noticed a droning/humming sound which I'm concerned may be indicative of a problem.

The noise keeps the same tone throughout the speed range and is audible (though subtle) from about 25mph onwards, but loudest at 61 to 63mph where it seems to become resonant and can be heard above the stereo.
that puzzels me as if it was a bearing then mostly the pitch will change with the speed of the vehicle?
 

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cold it be the DC / AC inverter? as the faster you drive the more electric power from the battery needs to be feed to the electric motor... (more Amps are going through)
 

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If the tone remains constant ( frequency of the note ), but more intensive as power is applied it would suggest something in the power delivery system rather than running gear which would vary with actual speed. I would tend to suspect the inverter as well.
 

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We have just had the transaxle replaced on our LEAF at 48k miles, this was a drone but sounded worse on left hand corners. It was under warranty, but would have been a £2k bill if not. The dealer who did the work also is the supplier for C&C taxis, so they have serviced the highest mileage cars in the U.K.(maybe world?) and ours was the first they had replaced, so not a common fault. Note the tone did not change with speed it just go louder during the months before we got it done.
 

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Discussion Starter #9
Just to provide an update, the Leaf was in with Nissan today. They found that all the brake discs were very corroded, and the front brakes are actually binding, hence the noise. Also explains why I haven't been getting very satisfactory miles per kwh!
 

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This has just started to happen with mine this week. It is when I drive through the village around 20 mph. Seems to come from the roof though that is just picking up a resonance. No changes to the road surface. It is going into Nissan next week so will ask them to check.
 

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it's always good to use the brakes (on an empty road) very hard by times to clean of the discs and keep the callipers from binding
 
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Discussion Starter #14
So getting the brakes sorted didn't fix the noise, and it started to get a lot louder.

Eventually got it properly diagnosed and fixed. It was the front passenger-side wheel bearing.
 

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Eventually got it properly diagnosed and fixed. It was the front passenger-side wheel bearing.
That could have disintegrated at speed with unthinkable results. Some years ago when I had fallen for the charms of one of those extended warranty policies I had a similar rumble noise which my mechanic mates diagnosed.as a wheel bearing on its way out. I contacted the warranty service as this was listed as being covered. However, they refused to pay, saying that the policy covered a failed bearing and not a failing bearing. They actually expected me to continue to drive at speed until it fell apart causing me to crash. They would then pay for a new £5 bearing once it had failed. I have never taken out a warranty policy since that experience.
 

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Had same with an extended £600 VW warrenty on a new van years ago when they only had a years cover.
Oil seal on rear wheel was weeping = sorry part too cheap to be covered (<£15)
Next van was a hiace , 14 years later all original when sold apart from service items+ tyres and front brake pads!!
 
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