Hello, just need some help. My car has been making a whining/droning noise between 30 and 40 mph for over a year now and I want too get too the bottom of it. 

It sounds like it's coming from the front of the car in the middle but it's hard too pinpoint. I had both front wheels bearings replaced as they were rough but this noise still remains. Replacing the wheel bearings made no difference too the noise. Under 30 mph there is no noise and over 40 mph there is no noise. 

The noise doesn't get worse if I steer left or right. The noise does get higher pitched up to 40mph. 

I have also rotated the tyres but this also made no difference. 

The gearbox oil was replaced about 6 months ago with the proper spec castrol 75w90 gear oil. This also made no difference too the noise. 

The noise also doesn't change if I put the clutch down or change gear or anything. It does get a bit louder in pitch when briefly accelerating but only very slightly louder. It happens in all gears and is definitely road speed related and not rpm related. 

Any ideas? Could it be something in the gearbox or maybe the driveshaft centre bearing? 

Cheers for any help

Clutch release bearing maybe ?

3 minutes ago, Ian Lanc said:

Clutch release bearing maybe ?

It's a possibility but wouldn't that be making noise only when pressing the clutch in as it's being put under load? The noise is there regardless of what gear or if the clutch is in or not 

You know anyone who works at an MOT station ? Suppose if you could get the chance you could put the wheels on the braking rollers and get listening around the car ?

2 hours ago, Ian Lanc said:

You know anyone who works at an MOT station ? Suppose if you could get the chance you could put the wheels on the braking rollers and get listening around the car ?

That's a good idea. Tbh it's got to be either something in the gearbox or the driveshaft bearing. It's been there for well over a year and hasn't really gotten worse or anything. Would it be worth putting a 2nd hand driveshaft in too see if that solves it? Think a driveshaft is about £25 used 

16 hours ago, Arkhangelsk1989 said:

Would it be worth putting a 2nd hand driveshaft in too see if that solves it? Think a driveshaft is about £25 used 

I'd never fit a secondhand driveshaft, you can't be sure if its any good in the first place.

I have bought a j&r driveshaft for £60 and am getting it fitted too see if that solves it. I know I'm just throwing parts at it but it's really baffling me because I can't pinpoint it. Hopefully this sorts it. If not it's got too be gearbox but I will just live with that if it is. 

On 8/16/2021 at 3:31 PM, Ian Lanc said:

I'd never fit a secondhand driveshaft, you can't be sure if its any good in the first place.

I have fitted a new driveshaft but it has made no difference to the noise. Tried swapping the tyres around but also made no difference. Definitely coming from the front of the car and both wheel bearings have just been replaced due to this noise. 

Only other thing is gearbox. What could be causing this inside the gearbox? Is it worth adding any additive? The oil is fresh with the proper spec castrol stuff. 

2 hours ago, Arkhangelsk1989 said:

Only other thing is gearbox. What could be causing this inside the gearbox?

When I had a droning noise back in 2016, I came across a thread that ended up finding the noise came from the final drive / differential unit, down in the gearbox. But I can not trace it now. My noise did turn out to be a wheel bearing, the speed range where it was obvious very slowly got wider, and eventually I could hear a change in tone when "weaving" the car. But that thread did show that a noise similar to bearings can come from the gearbox.

I clamped a microphone on top of the gearbox while testing for my noise. It made an appalling racket, like a worn out Morris Minor with spur gears, screaming and clanking with any change from drive to overdrive, but went quiet with the clutch in or with throttle set just between drive & overdrive. So I eliminated (to my mind anyway) gearbox noise on my car for the source of the drone.

7 hours ago, Tdci-Peter said:

When I had a droning noise back in 2016, I came across a thread that ended up finding the noise came from the final drive / differential unit, down in the gearbox. But I can not trace it now. My noise did turn out to be a wheel bearing, the speed range where it was obvious very slowly got wider, and eventually I could hear a change in tone when "weaving" the car. But that thread did show that a noise similar to bearings can come from the gearbox.

I clamped a microphone on top of the gearbox while testing for my noise. It made an appalling racket, like a worn out Morris Minor with spur gears, screaming and clanking with any change from drive to overdrive, but went quiet with the clutch in or with throttle set just between drive & overdrive. So I eliminated (to my mind anyway) gearbox noise on my car for the source of the drone.

This noise was here before I had the wheel bearings done so I got them replaced but made no difference. All 4 wheel bearings are brand new. Definitely got to be gearbox bearings then. The noise hasn't got worse its just noticeable. Might try some additive and see if that does anything. 

 

1 hour ago, Arkhangelsk1989 said:

Definitely got to be gearbox bearings then. The noise hasn't got worse its just noticeable. Might try some additive and see if that does anything. 

Gearboxes can make odd noises for a very long time before there is any real problem apart from an annoying noise that you probably only notice because you are tuned in to it. Repairing them is usually not an option, nor is a new one, so waiting for a known good used one is the only practical final solution. But the problem with narrowing a fault down by elimination is that there are several ways that a fault can get through. A resonance from some loose item not directly in the drive chain, to a similar fault in a replaced item. So the best idea is to do cheap easy things like trying an additive, or finding some way to do audio tests (like my microphone, which was not a very simple operation to do it safely while driving), or just seeing if the problem develops, unless a known good used box almost jumps out at you!

Wheel bearings are a bit safety critical, they are all that holds the wheel on and in place, and they can fail catastrophically (very rarely). I suppose a gearbox final drive could theoretically seize solid, with loss of control, but I have never heard of this happening. I think it is practically impossible while the car is moving.

Diffs were a really common issue on the small engined 306's...  One of mine was on it's 3rd gearbox when I sold it at 80k!  

The noise was awful on over-run, like someone running a stick along a metal railing fence!