richmod

So. I'm trying to understand exactly how gears and driveshaft work soI can problem solve the whine I have (get into that later). Can anyone answer the following questions?

- Is the driveshaft rotating when car is moving and
a)in neutral?
b) in gear with foot off gas?

- is the ring and pinion rotating when car is moving and
a) in neutral?
b) in gear with foot off gas? (pretty sure answer is yes here, but asking anyway)

So, without going into my long rear-end/gear history, here is what my car does:

Whine/flutter type sound from back half of car:
- on decel/coast only
- fades in around 55mph, worse at 50, fades out about 40 mph
- goes away immediately on even slight throttle
- goes away if put car inneutral
- doesn'tgo away/changeif turn overdrive off

I'm trying to decide if this is gears, cause if it is i'll just upgrade and e done with it. But I will be p*ssed if I do that and the whine is still there. i'm also a littel concerned that it's the tranny, although my gut tells me otherwise.

TIA

smythge

If the car is moving the ring a pinon are moving and so is the drive shaft as they're are all connected together. if one spins they all spin.

richmod

So why would putting the car in neutral stop the whine?

hogpowr

load

smythge

+1whatyou're describing isgear whine, comes in at different RPMS and changes with the amount of load the rear end is under.

richmod

Okay, thanks.

So, by the same token, couldn't the whine be the driveshaft or tranny since they work on the same load principle? i doubt it's tranny since it doesn't change with rpm at same speed (turn off OD), but how 'bout drive shaft or even u-joints?

06VistaBlueGT

Im my experience, if it's whine, it's gears. Driveshafts will vibrate if there is an issue and u-joints will clunk if they're bad.

Still trying to figure out what goes chitty chitty bang bang

Wizzle07GT

do you have stock gears or have you changed them?

richmod

stock. this is actually my second rear end, as the whole differential was replaced due to other probsI won't get into. this pumpkin has never been opened.

Gene K

If this is the stock rear two-piece driveshaft in a GT it could be the driveshaft carrier bearing.
However this normally whines on throttle I believe.

The number one suspect is the ring and pinion in my opinion.