3.0tdi manual differential issues?

elf458

elf458

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Hi all,

New here, migrated from the VW world to get myself a quattro.

Ive had a nightmare with cam tensioners starting to rattle all of a sudden, changed the top two and now the lowers are starting to grumble too. Now its got another noise coming to the surface, and i really dont have the experience with the quattro system and searches aren't getting me anywhere so here i am.

It seems that its slowly developing deep bassey vibration under load in high gears, mid rpms and full load... at low speeds or higher rpms with full load, no noise. Its not the normal CV joint characteristics or wheel bearing sounds so i'm thinking something to do with the diff?

If anyone has any experience with the quattro systems failures or any ideas what to investigate then please do advise.

Thank you!
 
Welcome to the nuthouse pal.....someone should be along soon that maybe able to shed some light on your problem!


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sounds like it may be clutch / DMF related. If it's occuring at the point of peak torque 1700-2500 RPM and when you are accelerating hard that coincides with peak torque.
How many miles has the car done, is it the original clutch ? .
 
Thanks for the reply deserstorm.

Its got 80k on the car and supposedly had a new clutch from previous owner 5k ago, although it has had a new performance map on it. The pedal feels fine, no vibrations at all on the foot, and not like any failing dmf I've experienced before but i just dont know myself
 
Who did the remap? Do you have a boost gauge on the car?.
Could be compressor surge on the turbo. I used to get this sometimes with my mapped Passat. If you have too much boost at low RPM with a high load on the engine, the boost pressure increases to a point where the flow on the turbine is not high enough to maintain the boost pressure. So the turbo slows as the boost drops the turbine then accelerates again.
This happens very quickly and can be seen on a boost gauge as very rapid changes in boost. It feels like a shudder through the whole car. The best way to get around it is to change down gear to reduce the load on the engine so it doesn't labour.
Reducing the amount of boost at those RPM where the problem occurs can also help.
This is quite a common issue on tuned diesels. People try and drive them on the torque.
If you want to accelerate quickly and the car is loaded or pulling up a hill, change down.
This can damage the turbo as it can snap the turbine shaft due to the rapidly changing speed of the turbine and compressor wheels.
 
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JF Automotive did the remap. They have a decent reputation locally. No boost gauge but im pretty sure its not that. It doesnt follow the nature of a pressure boost spike, it follows the torque output spike. Plus i think the noise is too loud to be that, it really seems like the drivetrain somewhere. I was hoping there would be a shim or transfer joint or something that is prone to deterioration that i could check/replace while im removing the box to do lower timing chain tensioners... but quattro is new to me.

I will get a gauge temporarily connected up at weekend as ive got a home workshop and mountain of spares from old modified diesels. Is there a line thats good to tap in to? The actuator is electric so i doubt has a line there. I will work it out but if anyone knows the secret to save me time then awesome!

I will definitely check the clutch and dmf (not that looking gives away much) when box is off - can i ask what clutch you run on yours? And out of interest, what kind of output can a standard setup handle?

Thanks for all the info
 
Karl, ive read through loads of your posts and your thread and seems likely im finding alot of similar info relating to dmf issues. Gonna get looking into single mass kits. i understand your prob on oe clutch seeing as your on b8 chassis, so no need to answer that one. thanks for all the info. If you know of a kit relevant for me do let me know but otherwise thanks a million bud!
 
Quick suggestion try recreating the noise and select neutral in the gearbox and release clutch so no load is on the gearbox and see if noise goes
 
GDCAUDIA4B7 its only under load. letting off throttle or using clutch the noise wont be there... what is your trail of thought?
 
This issue is starting to bug me - has noone really found a cure for the rear end rumble at low revs in high gears?

Ive found someone local on here (Ubor) that has the same issue. Definitely not clutch related. We are a bit stumped and just guessing at things at the moment.
 
Having actually felt it in the car yeah it is definitely the same but mine is more pronounced.
Background on mine as this thread made me contact you....

Car is a 3.0TDI BKN A4 Avant. I got it around 10-12 weeks ago. Few issues but nothing major however on the way home I found under certain circumstances it made a juddering feeling like it was coming from the back N/S of the car. Worked out I could replicate it as follows:

Any high gear (so 4th/5th/6th) with the revs at around 1500rpm - if I put my foot flat to the floor it will judder (quite strongly in mine) as it accelerates up through to about 2200rpm where it fades. If at any point when it is juddering you release the throttle a bit it goes. The judder in mine is stronger in higher gears. While 1500rpm is about the optimium to feel it I can make it do it anywhere in the 1500-2200rpm by putting my foot flat down with it fading as it gets about 2200rpm. If you go from a standing start and push up through all the gears you never get the judder at all. The car doesn't feel slow at all in normal driving.

Took it to a specialist who said it was like "having a bass bin in the back" and also thought (although hard to quantify) the normal Audi judder at lock on at slow speeds was strong. They checked the drive shafts, diffs, and prop - all looked fine. Looked at the N/S rear bearing which felt a bit iffy so that was replaced. Same issue. They thought it was the diff (ETS/01R) and did an oil change. New part was too much so took it back for a bit. Had it 4 wheel aligned (front O/S was out) and after the judder felt like it was across the whole back of the car not just the rear N/S.

Clutch was going when I got it so had to get that replaced and as DMF was a possible cause it made sense. Got that done no difference.

[Probably totally unconnected] Car was making a bit too much smoke I thought so got a vagcom and connected it up. Fuel Temp Sensor was faulty (reading -15C) so changed that. Did reading on forums and came across the Gerp/M5NUT EGR posts (very helpful). Noticed the MAF readings where out like Gerp. Changed the MAF sensor. Cleaned the throttle adaptor to clear the two EGR holes and air intake pipe. MAF readings better but could see the EGR valve was sticking in positions. Currently car apart and cleaning the intakes flap bottom section, EGR cooler, new EGR flap, and EGR valve, and 6 glow plugs (as 3 were faulty). Have spotted a leak in the turbo exhaust gasket which will be replaced after.
Honestly tho - I think this is all just improving the smoke issue not the judder. But as it needed doing and in case it is related.

Garage says diff but because of cost that would be second hand and part of me just isn't convinced as it only does it in a very specific set of circumstances?

Like Elf says bit stuck....
 
We will get there Ubor.

Im having other conversations on TDIclub forum as there are a few others with the same issue. The only person that seems to have got around it is by fitting a larger turbo and avoiding the power in the dreaded part of the powerband but seeing as yours is worse than mine with slightly less power there must be a part that wears, exacerbating the issue. Its only a matter of time until we find the part or someone that has previously.

Thanks everyone
 
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