Whine...

[RmcMills]

Hello all!
Just a quick one, on my 2000 s4 there is a quite loud whine in all gears when accelerating or maintaining a constant speed. As soon as you begin to decellerate the noise stops completely. Also the transmission seems to bang when chaging acceleration at low revs at low speeds. Has anyone else experienced this, and can shed any light on the situation?
Cheers Ollie

 

[Siena]

Your front differential bearings are shot.

I had the same with my old 5-speed, mine was just first though, was quiet unloaded, but whined once you stepped on the gas.

You'll need to replace the front differential bearings, it'll only get worse over time.

 

[RmcMills]

Ahh that doesnt sound cheap at all!
Any ideas on cost?

 

[Siena]

I've just bought a repair kit for a '99 2,8 Quattro, I'll look at the invoice, see how much it all came to.

 

[Cruz]

Yep defo sounds like diff bearings to me.

Had similar on mine but was lucky enough to get it sorted from the place i bought it from under warranty.

Certainly not gonna be cheap unfortunately mate.

 

[s4marsh]

i dont really want an answer to this question if its bad news but when going in reverse you get the usual whine on most cars dont you, whats all that about then????

 

[aragorn]

Ours whines on overrun in first, but goes quiet when under load... Whats goin on there then?

S4Marsh: Reverse gear is "streight cut", rather than helical like the forward gears, and its this that causes the noise. Nothing to worry about. Some race gearboxes have streight cut gears in all gears, if you listen to a GT or touring car you'll hear that noise as they accellerate.

As for the OP, it might be cheaper to find a low mileage box and swap it out?

 

[s4marsh]

aragorn your one smart mo fo.. i've heard the term straight cut box in relation to rally/gt cars and such like yes and sort of pretended i understand it but dont really...lol a bit like my g/f then

 

[aragorn]

This is a helical gear:

http://en.wikipedia.org/wiki/File:Helical_Gears.jpg

and this is a streight cut (or spur gear):

http://en.wikipedia.org/wiki/File:Gears_animation.gif

You see on the helical gearset the teeth are angled, which reduces noise because the gear engages more gradually.

 

[Siena]

Aragorn, RMC's car is an S4, so an 01E 6-speed, not cheap to replace.

Differential bearings aren't bad to replace, but tranny needs to be pulled, and the case split into torsen, mid section and bellhousing, as the pinion shaft has to be removed to replace the differential bearings.

On this 2,8 quattro, I'm replacing the pinion bearing too, as a precaution.

 

[aragorn]

ah ye, those are expensive.

I guess its just a case of weighing up the costs of replacement with cost of rebuilding the box in terms of labour and the replacement parts.

I really hate gearbox internals! They more often than not need dozens of special tools to dismantle them, and tolerances of the parts need set extremely accurately or it all nicely welds itself together in about 5 miles

 

[RmcMills]

Ooh not cool. Looking at a few grand minimum would you say?

 

[aragorn]

Used boxes can be had for 600ish

Although this could be a bargain:

http://cgi.ebay.co.uk/AUDI-S4-S6-20...s_SM?hash=item53dc04399c&_trksid=p3286.c0.m14

 

[s4marsh]

rmc i hope you find a reasonable outcome to this and cheers aragorn for the gears post..i can stop pretending i know now cos i do.....lol

 

[Siena]

Ooh not cool. Looking at a few grand minimum would you say?

Hardly. I'd say you're looking at £380 - £550.

 

[RmcMills]

Ah ok cheers, Thats not too bad then. I'll get it to my mechanic in Northallerton and see what he reckons to it all. Good find there aragorn, you must have sharp eyes!
I dont seen to be having a lot of luck with this s4, had it 2 weeks and its already needed new brake and clutch master cylinders :/