2006 1.9 PD 155K miles 5 Speed Manual.

 

Approximately 300 miles ago I noticed a faint hissing sound coming from the passenger footwell area whenever I depressed the accelerator pedal when driving.

 

That progressed to a drone from the front left on cornering right, like a wheel bearing going bad.

 

In the last 50 miles there's a drumming sound from the same area that's got so bad pedestrians look round.  This sound is consistent with road speed not engine RPM, in all forward gears but only when on the power, when coasting in gear or selecting neutral the sound disappears.  Gear changes have become intermittently rough, not problematic but noticeable from usual.

 

I've removed and examined the left driveshaft and can't find fault with either CV joint.

 

With the car on axle stands and the engine running in gear the gearbox sounds a bit rough using an improvised stethoscope, predominately from the front left area (bearing area?).

 

About to remove the right driveshaft to isolate the gearbox and see if there's any change to the sound although at this stage I've pretty much accepted the gearbox is shagged out and will need swapped for a scrappy item.

 

Does anyone have any words of wisdom regarding the likely cause given it doesn't fit the typical symptoms of a bad wheel bearing or outer CV joint noisy on full lock?

 

Bad output shaft bearing?

Is it possible that the noise is still coming from the front hub area but disappears when coasting as it's no longer under load?

Sounds like the crown wheel and pinion, well whatever the equivalent differential drive gear is called in the FWD setup.

 

I'm sure I have read of catastrophic failures where the transmission case has fractured when things make a bid for freedom and photos showing the parts that had caused the meltdown, bolts or rivets securing the planet wheel carrier to the crown wheel perhaps?

 

My rationale is that the noise is only under load and in all gears which rules out mainshaft or layshaft bearings.

 

I'm sure someone will recall with detail what I only have a vague recollection of.

 

I know how embarrasing it is to have pedestrians turn around and wince while you are trying to isolate and diagnose the cause of the noise.

Without any experience of said symptoms. How about clutch/DMF as being the likely cause. Have you had to change a clutch/DMF? Before my DMF/clutch was changes I used to get a buzzing from the glovebox side of the car when accelerating. Once DMF was removed it as noted it was very wobbly/on its last legs. Very common issue on our era PD cars 

Thanks for the input gents.

 

The box running without driveshafts sounded like a train's wheels rolling on straight rails which confirms in my mind that something has let go, surely a good box should sound smooth without mechanical rumbling.

 

Box ordered from a scrappy so I've a couple of days to prep things for a swap.

 

If only it was this easy:

https://youtu.be/qdHp1lFrnEk?t=60

Hissing? Could it be a vacuum leak? Are you noticing any decrease in power?

I am going with start of gearbox bearing failure, no decrease in power.

Box from scrappy fitted, so far so good, fingers crossed it's a goodun.