Vantage v8 Gearbox hum, like a dying wheel bearing

[Mish 80]

Hoping someone might have some ideas about my issue, other than a replacement gearbox.

2005 manual V8 Vantage, 29,500 miles. Tires are all M PS5 dated 2024.


Issue:
Wheel bearing type low frequency hum from rear increasing with speed.

• Very defined on motorway 50+.Increases DB with speed and constant in tone.
• Became apparent to me about 900miles ago. Cant say if its got worse since, as you cant 'unhear it' now.
• Does not change when cornering.
• Does not change when applying torque, coasting, neutral or braking.
• Same in 3rd and 4th/5/6. Possibly louder in 4-6 but engine noise starts to compete at high revs while in 3rd. 
• Seems to increase to peak after car is running for 30mins but no worse after 1hrs. I guess as the gearbox/diff gets upto temp.

Original job sheet:
Rear wheel bearing check + replace.


Independent garage investigation:

• no wheel bearing issues found
• Car suspended and ran in gear, noise apparent.
• Stethoscope used to narrow down the noise emitting area to the torque tube interface to gearbox. 

Recommended course of action:
check + change torque tube bearings. ~8hrs labour.

Twin plate AMR clutch added to job sheet given the process/labour its basically the ideal time to switch a clutch on a nearly 30k car . Everything taken down and re-seated including drive shafts.  


Reassembled.
Same noise, Trans axel oil changed.

Same noise, slight twin plate chatter now present(as predicted).

Questions

Anyone got any ideas or things to check next, beside obtaining another Graziano gearbox ?

An additive is unlikely to help but as a cheap option, I can try if someone can vouch for one for a trans?

I couldn't find a suitable gearbox specialist, any recommendations or parts sources/sellers other than ebay ?

BR and Aston Workshop have been amazing with suggestions but I cant keep bugging unless I have something billable for them to do.




 

[CatalystV12V]

Try these guys.

http://www.astonmartingearboxes.com/contact-us/

[Calinours]

OK here goes...

Mish 80 said:

Hoping someone might have some ideas about my issue, other than a replacement gearbox.

2005 manual V8 Vantage, 29,500 miles. Tires are all M PS5 dated 2024.


Issue:
Wheel bearing type low frequency hum from rear increasing with speed.

What's behind the wheel bearing assumption?

• Very defined on motorway 50+.Increases DB with speed and constant in tone.

suggests wheel bearing, half shafts, gearbox elements rotating at fixed speed, carbon driveshaft/torque tube or wind induced resonance.

• Became apparent to me about 900miles ago. Cant say if its got worse since, as you cant 'unhear it' now.
• Does not change when cornering.

almost, but not quite, rules out wheel bearings. Rules out fronts but not rears.

• Does not change when applying torque, coasting, neutral or braking.

in general, rules out specific ratios if this is true in all ratios

• Same in 3rd and 4th/5/6. Possibly louder in 4-6 but engine noise starts to compete at high revs while in 3rd. 

see above. worthy of efforts to clarify.

• Seems to increase to peak after car is running for 30mins but no worse after 1hrs. I guess as the gearbox/diff gets upto temp.

Original job sheet:
Rear wheel bearing check + replace.


Independent garage investigation:

• no wheel bearing issues found
• Car suspended and ran in gear, noise apparent.
• Stethoscope used to narrow down the noise emitting area to the torque tube interface to gearbox. 

Recommended course of action:
check + change torque tube bearings. ~8hrs labour.

Twin plate AMR clutch added to job sheet given the process/labour its basically the ideal time to switch a clutch on a nearly 30k car . Everything taken down and re-seated including drive shafts.  


Reassembled.
Same noise, Trans axel oil changed.

Same noise, slight twin plate chatter now present(as predicted).

Questions

Anyone got any ideas or things to check next, beside obtaining another Graziano gearbox ?

An additive is unlikely to help but as a cheap option, I can try if someone can vouch for one for a trans?

I couldn't find a suitable gearbox specialist, any recommendations or parts sources/sellers other than ebay ?

BR and Aston Workshop have been amazing with suggestions but I cant keep bugging unless I have something billable for them to do.


What do BR say? Love or loathe him, Mike knows these cars as well as anyone.

Key is to determine if it's the gearbox internally or input/output shafts (or more specifically their bearings)

An idea is to look hard at one of the gearbox output (half shaft) bearings. Look for evidence of previous transmission oil leaks.


 

[Mish 80]

CatalystV12V said:

Try these guys.

astonmartingearboxes

Thanks
They seem to be out of business according to Company's house. Emails bounce and numbers unconnected.

[yvr]

A deep dive into the internals of a similar, if not exactly the same, transmission...

https://www.youtube.com/watch?v=tLhvbrA7uRQ&ab...

Fascinating and well presented

[Mish 80]

Thanks for the input Calinours.

What's behind the wheel bearing assumption?
Just previous experiencebon on other cars
.

suggests wheel bearing, half shafts, gearbox elements rotating at fixed speed, carbon driveshaft/torque tube or wind induced resonance.
How could I/they test these?

Can the prop shaft be distorted? could explain why the drive shaft bearings looked worn? Guess theyd break catastrophical, rather then deform?
Could also be gearbox bearing side I suppose, wobbling the prop.

• Same in 3rd and 4th/5/6. Possibly louder in 4-6 but engine noise starts to compete at high revs while in 3rd. 

see above. worthy of efforts to clarify.
I'll drive some more and try and record it.




What do BR say? Love or loathe him, Mike knows these cars as well as anyone.

BR-Mike, I'm sure is inundated with calls and queries so I tried to keep it short.


His concern on the investigation done was the way sounds travels across the car easily and could send you in the wrong direction. I didn't know my garage had used a stethoscope when talking to him sadly. Might have changed his next steps.
His first suggestion was checking the noise is present in all gears. Which I will retest but fairly sure, when sitting with a tech it was there in 3rd when the car was fairly cold. Going home, as if when trans oil heated up, it got more annoying


Key is to determine if it's the gearbox internally or input/output shafts (or more specifically their bearings)


An idea is to look hard at one of the gearbox output (half shaft) bearings. Look for evidence of previous transmission oil leaks.

Isn't the outcome, really the same, replace gearbox anyway? Or are the outer bearings somewhat replacable? Half shafts, in situ?

I've asked if they noticed anything, but doubt they looked too hard if they thought they found the smoking gun on prop bearings. Given the reputation of the gearbox is pretty good I think.



.


Given the labour costs I feel like I need a spare prop and trans to swap out to minimise ramp time, then spend months reselling them online again. Half shafts could be the easiest to test first but I think least likely. BR is a 5hr drive sadly.
 

Edited by Mish 80 on Friday 15th November 18:50

[Calinours]

BR a 5 hr drive? where are you? - there are some other useful specialists but for stuff like this Mike et al do come into their own.

Assuming you are able to rule out rear wheel bearings, which will generally make more noise in the corners, I guess a plan would be to try to confirm that the noise is present in all gears, (ie to confirm that it is not a particular gear ratio), then determine if it changes at all under load to 100% confirm its powertrain.

Then, if you can, confirm whether the noise is engine speed dependant (suggests propshaft and its bearings) or road speed dependant (suggests half shaft and its bearings).

Best of luck

[Mish 80]

Thanks again for the advice

Same tone at 50mph 3rd and 4/5/6.
Faster ground speed makes it louder.
Same accelerating, stable cruise, slowing, coasting in neutral.

It increases I think, after a pushing the car in a spirited way, maybe as the diff gets hotter?
Does the diff increase and decrease temperature within such a short amount of time e.g. a few seconds, Like a 0-60?

Am in Newcastle btw, my local, Aston Workshop gave it a shot with the prop bearing replacement + twin plate. Which involves taking the Half's off, presumably they'd have noticed them-then

Edited by Mish 80 on Sunday 17th November 12:34

Edited by Mish 80 on Sunday 17th November 12:38

[Calinours]

Sorry man, from what you say it seems to be pointing to the transaxle diff itself

[CatalystV12V]

yvr said:

A deep dive into the internals of a similar, if not exactly the same, transmission...

https://www.youtube.com/watch?v=tLhvbrA7uRQ&ab...

Fascinating and well presented

Oh! I spoke with them last year about a car I was thinking of buying. Seemed very knowledgable.

[jeremyc]

What changed around 900 miles ago - was any work carried out on the car?

When were the tyres replaced (you say they are dated 2024)?

[Mish 80]

I got the car in the summer with 28k miles. Switched out all the tires, as they were 2016 Bridgestones. Had the tracker disabled and added cruise control. I did lots of short country side trips, mostly with the windows open thinking about it.

Then did a 1200mille road trip to and around rainy Scotland on alot M roads sat on cruise where I started to notice the hum.

I think it is a case of, once you hear it, you can't unhear it. I've done 400 miles since and don't think it's gotten progressively worse but am very aware of it. The service guy confirms its abnormal than normal(like a wheel bearing starting to go).

I'd hate to switch a trans out and the 8hr labour if it was something serviceable!

Suppose I'll see if it gets worse and it'll becomes more clear what it is.

[jeremyc]

Did you notice the noise at all on the old tyres?

[Mish 80]

Nah, switched them same week while detailing it (polish,wheels off, arches, ceramics etc etc).

My first Vantage, so it might have always been there...

[cliffords]

I don't have your car ,but I have experienced something like you describe and it was in fact the differential. It's noise basically travelled along the propshaft and ended up at the gearbox.
Took a lot of hunting and listening, eventually the diff got so noisy it could be detected at the diff, however it started with a gearbox noise .
Replaced diff only ,noise gone .

[eldavo]

Mish 80 said:

I got the car in the summer with 28k miles. Switched out all the tires, as they were 2016 Bridgestones. Had the tracker disabled and added cruise control. I did lots of short country side trips, mostly with the windows open thinking about it.

Then did a 1200mille road trip to and around rainy Scotland on alot M roads sat on cruise where I started to notice the hum.

I think it is a case of, once you hear it, you can't unhear it. I've done 400 miles since and don't think it's gotten progressively worse but am very aware of it. The service guy confirms its abnormal than normal(like a wheel bearing starting to go).

I'd hate to switch a trans out and the 8hr labour if it was something serviceable!

Suppose I'll see if it gets worse and it'll becomes more clear what it is.

Take it to Dave at Autolink (Back Goldspink Lane in Sandyford) before going further afield - his knack is finding and diagnosing weird problems on high end cars.