carnagarve

Folks, totally new to the forum so please bear with me as a newbie! Have a 2008 S8, 120K on it. Fairly good Audi history. Yesterday I was driving the car for approx. 30 miles from cold as normal and when I came to a halt at traffic lights felt something like a jerk. Nothing affected so I continued on my journey a further 200 miles on motorway. I was decelerating from @80 mph when I could hear a very loud squealing noise from engine. Pulled over and noise was still evident whilst idling and in park position but was not as loud and intermittent. Continued on motorway again and noise went away until I slowed again. Took car straight to Audi dealer nearby and noise was there. Very high pitch from rear of engine. I tried turning off heater and AC to check it wasn't belt. It really sounded like a squealing belt. Mechanic thought perhaps an alternator bearing but would require further investigation on ramp; left car for inspection and get a call today to say they believe the noise is coming from gearbox; they need to do a gearbox oil change to inspect oil at a cost of euro 875 as an initial investigation! I'm scared already at the thought of what's to come.


I'm wondering if anyone else on here suspects what may be causing my noise; car dives and changes perfect; not down on power or any EML lights etc. I'm no mechanic but think it's unlikely that a gearbox noise fault would be there in park position; might it be the gearbox oil cooler or another belt of some description. Please help if possible as I need to make an urgent decision to remove it from dealer before costs escalate drastically!!! If it requires a gearbox ill take it to independent specialist for second hand unit.

Shamoye Lewis

if its manual its probably just the throw-out or pilot bearing.....
automatic tranny dont really make noises when they need oil, they just don't move that's all, if the oil needs to change and the level is good it still should not be squealing... especially at stand still because nothing is really moving....

they believe is not a good answer they need to be sure and if you act stupid you will get robbed blind....

when the car is stand still and in park when you rev it does the noise go faster or in motion/speed with the engine revs...

you need to double check some stuff...

MP4.2+6.0

I actually did have a noise in my 2000 C5 A6 4.2 with quattro. That was a 5 speed tranny, but diff wise fairly close. Your description reminds me of that same experience. It only happened once or twice ever; it was colder at the time. Since it went away I never chased it down. Car later had an apparently unrelated transmission failure--like almost all C5 and D2 4.2's--so who knows if the ZF rebuild took care of it. Car is still on road today.

Back on yours, I would in fact check the diff fluid levels. As an S8, you should have the system with the external lines and cooler that effectively ties the mid (Torsen) diff and the front diff. together. And thus a leak in either means both front and mod diff. shared fluid then ends up low. Most common leak is probably the rear seal at the back of the mid (Torsen) differential, although I have heard of few if any so far on the D3.

A good ZF shop can do the same work and checks. In the U.S. that is usually more cost effective than a dealer, and the ZF guys probably know more about the whole tranny and diff set up anyway.

Shark_V8

I'm gonna guess the T/C (torque converter) or a pump inside the tranny is on its way out. Correct procedure to look for evidence of metal or broken up bits in the fluid.

There are no belts that could squeal, that was back in the 70's when V-belts were in.

Drop the tranny, install reman = $6K min.

I am not sure I would do a second hand tranny just to save a few thou. These are complex, labour is $$$ so the only guaranteed is a factory reman. That's what my brother did with his A8 after looking around.

carnagarve

Well Audi contacted me to advise that the oil is clear of any nasty metal particles. They now think it's perhaps a ceased pulley of some description. The noise is intermittent and usually when the car is warmed up. Glad it's not the gearbox itself although still not clear what the issue is exactly. Whilst the investigations continue so will the $$$$

Mark steer

im having the same issue with my 07 s8.
Did you ever get to the bottom of your issue

PaulW

If I had to guess, I would say it's the drive for the AC compressor which comes off the back of the engine and the drive is on the bottom left of the engine and drives the compressor which is forward. If this just came about in the very cold weather, I bet it something in the drive assembly, I heard on some cars that the grease degrades on the power take off over time and it can lock the drive up.

Pictures of said compressor:



https://www.ebay.com/itm/2007-2011-A...M/182759864996

Worth a look or hear.