VXOC Astra-J/GTC

Full Version: Flapping Sound when driving.
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Hello Everyone,

I do have an Hatchback Astra J 2015 1.4NET with auto transmission. 

I did detected a flapping noise like as you are driving something stick on the tires or it sounds like there is some lines on the road and you are passing on them. 

I know it's a very low chance find this kind of a sound issue without hearing it but I'm out of ideas to tell to service to check. 

So I made below checks and fixes: 

- When I first noticed the sound I re-balanced the summer tires on the tire shop, summer tires are balanced off the car and back tires are balanced again on the car.
 
- One month ago I switch to winter tires sound increased become more noticeable also balance work is done again. Also asked to check the rims if there is any bend parts but there isn't.
 
- I was low on front discs and pads so they all changed, back discs and pads seems fine for now.

- While the car is on lift I turned them to hear any problem with the hub bearings , also asked service guys to check them and they didn't hear or find any problem. 

- Sound can be heard at best 6th gear 2500 rpm - 3000 rpm  in between 100 Km/h ~ 140 Km/h. Over or under these ranges probably continues to do but I can't hear it over the engine sound.   

- I did try applying brakes a bit while keeping the speed to feel if any vibration increase or decrease. Nothing significant there... 

- Hard on corners increase the sound and make it more hearable with a higher pitch.

- I put it to neutral while going (I know, not good idea for the a/t) but still hear it the noise. 

I'm thinking may be problem is with the hubs bearings may be I need to check on load, but how? (all factory hubs at the moment no change or after market hub installed)

Also may be I need to check alignment settings for wheel camber & caster but when I leave steering alone for test it goes straight at the speeds that I hear the sound.  

[url=https://blog.firestonecompleteautocare.com/alignment/alignment-settings-wheel-camber-and-caster/][/url]More scary thoughts... May be problem is caused by diff or gearbox, I don't think it's the engine since when in neutral it continues  also I want to believe it's not gearbox. 

So if anyone have another opinion or something else to check, I would be very very appriciated... 


Happy new year... 


Regards.
could be the diff bearings ?