forum.audiv8.com Foren English Audi V8 Forum V8 Quattro Axle Woes

Hi everyone,

I recently took my 1990 3.6L V8 Quattro in for a complete mechanical inspection and had a list made of all issues the mechanics found. The two worst problems are that the transmission is stuck in electrical limp mode (which I'll tackle on another thread later) and that the front axle is badly corroded and apparently needs replacing.

Noticeably, the front left outer CV boot is torn open and the joint is incredibly loud on right turns, to the point that the mechanics have warned me that the CV will fail soon and possibly jam. However, when I asked about getting the axle or CV replaced, I was told that the 1990 V8Q's use a unique axle that is long out of production, and that the only option would be to find an identical donor car to use for parts, or simply, that I should scrap the car and move on.

That said, another friend with a V8Q told me the axle of the C4 series Audi 100/A6 was the same, and that it could be directly swapped. Is this true? How about just replacing the CV joint with a C4 series part?

It's worth noting that my UFO brakes have been swapped for G60's.

Thanks in advance for your advice!

Hi Jordan and welcome to the decreasing V8 community!

It would be easier to answer your question(s) if you named the part numbers matching to your car. So please mind that: http://www.partscats.info/audi/en/?i=cat_vag_models&brand=au&number=1488&set=1490&ein=1990&f=90&hauptgr=1234567890&hg=4&grf=003700090&bf=%2037&hgug=407&ug=07&parent_id=357409

Regards

Hi Tim,

I'm not an expert, but I believe it would be part number 441407271M (14A) on the diagram you sent me.

After some late-night searching on Google, I also think I found the elusive CV joint which is discontinued in North America: Is this the one?

Hi Jordan,

I can try to find the matching part numbers for you. But I need your VIN and the gear box ID letters for that. You may transmit it with a private message or eMail
(click my Name and you'll find the opportunities)

The driveshaft 441407271M is available in Germany (aftermarket stores). The joint of your link is an inner drive shaft joint. I guess it will not solve your problems. And I'm not sure whether it would fit to your car.

What is your location?

Regards

I'll check my VIN number when I get off work in a few hours. Where would I find the transmission code numbers?

I'm located in Victoria, British Columbia, Canada.

Thanks!

Sorry, the gear box ID seems NOT to be required

You mean because the outer CVs are all the same?

I've been wonderering why you requested the gear box ID

The inside CV's are not the same at all... the front ones are till beginning 1991 108mm adapter (Rzeppa), later they are 100mm (Tripode).

Hi Tim, Roy,

My VIN # is WAUKE544XLN010723.

Regarding the front axle; the mechanic told me to replace the whole thing, but these aren't easy to find in Canada anymore. I'd like to rectify the "clicking" noise I'm getting turning sharp right, as well as replace the lower control arms (as I'm experiencing bad bump-steer when I hit uneven pavement).

Roy, looking at your smugmug profile, I see you've had transmission problems in the past? Did you manage to fix yours?

Thanks for all the help gentlemen

I'm rather cynical when it comes to the majority of garages, repair shops, etc. I get the impression that many are really just component fitters, and lack the skill for proper repairs.
Finding a complete, new shaft at sensible price may be difficult or impossible. Fitting a used one may leave you open to the same problems soon.

Find a local driveshaft specialist, and see what they say.

In Antwort auf:

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Roy, looking at your smugmug profile, I see you've had transmission problems in the past?

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There are no pics about transmission and its problems...

?

Well... last year I crushed my 2nd V8, so I get a other one (for Winter and for the case I do some maintenance on the 1st V8)... pretty low price BUT the transmission has been cracked somehow - reverse okay, but no way to drive forward, so I think it's the clutch A in the gear box which it's cracked.
The scary thing is, there are no chips in the ATF or its filter at all... maybe the last owner changed it by trying to repair it...

So I will replace the whole thing - yesterday I saw, that my replacements are all the newer transmissions (I have 2 of them) then the one in der car... f**k!

Lucky I am, I found 2 axels with the newer adapter (the one with 100mm Tripod) in my storage.

I hope that will be the only difference... today I go to concreting my new stairs, maybe later or tomorow I will see more... just a bunch of screws need to be removed.

Clicking noise at turns, according to driving speed is definitely generated by worn outer drive shaft joints. If inner joints are worn, they generate vibrations but no clicking noise.
The outer joints are not a big deal to replace.

But I'm with Mark. You need an experienced mechanic for proper diagnostics and fittings. Bad bump-steer may of course be caused by worn bushings and ball joints but also by worn shock absorbers.

I'll try to be back with some part numbers.

The matching part numbers for outer joints are: 4A0 498 099 and 4A0 498 099D
They fit to different 100, A6 and V8
This joints are easily available in Germany if you can't them in Canada or the USA

In reply to:

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There are no pics about transmission and its problems...

?

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Sorry. I saw a photo here that showed your transmission display in "PRND321" so I assumed you had experienced the dreaded "limp mode" in one form or another...

In reply to:

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The matching part numbers for outer joints are: 4A0 498 099 and 4A0 498 099D
They fit to different 100, A6 and V8
This joints are easily available in Germany if you can't them in Canada or the USA

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Wow, these look exactly like what I need! I will speak to my mechanic about having a pair installed. I just have to wait for a few more paydays to come: another repair has suddenly taken priority - my radiator line blew a couple of days ago

Nope... this are pics for a manual to read out the fault codes without VAG-Com or VCDS or whatever.

Watch attachment...

For you without the knowledge of the literary language from germany, austria and switzerland: KLICK ME

In reply to:

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Nope... this are pics for a manual to read out the fault codes without VAG-Com or VCDS or whatever.

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Sweet!

I actually just got my V8Q back from a mechanic today ... he blinked out all my error codes, so this guide will come in handy.

Lets just say there were many things wrong. Enough that I'll need a new thread to list them, as they're all related to my limping transmission.

I think you get 2111...?

Forget it, if the enginge run, this failure can't be for shure, before read out the codes, you should hit the starter (and let ignition on) or let the enginge run.

I think the mechanic actually had the old VAGCOM scanner. Because the numbers he wrote down are in long form:

00516 001 - Closed Throttle Switch
00513 003 - Engine Speed Sensor
00518 007 - Throttle Position Sensor
002 002 - Kick Down Switch

All my ABS sensors are offline too. I attached his report if you'd like to check it out.

I'd try to clean the connectors on top of the engine, front-sided. There are two of them, a larger one and a smaller one. Disconnect them, clean them if required (they may be corroded), apply some sort of contact spray, let everything dry and reconnect it.

This is often the cause of many troubles, from "goatish" accelerations over alternativing revs to gearbox problems. It can also cause the gearbox to switch to emergency mode.

Regards

Bastian

I'm in agreement with Bastian about checking and cleaning connections. The throttle pot has a wide (6pin?) connector, and is prone to water damage if the rubber boot on the connector is damaged. It's at the front of the engine. It's fairly easy to access and clean the contacts of the connector, but the unit is sealed.

The gearbox speed sensor and the O2 sensor are also able to get a bad connection due to a build up of grime. The O2 especially if there is even a small oil leak at the rear of the engine.
In both case, disconnecting, cleaning off and then drying the connections afterwards may help you.

Bastian, you're a genius.

In looking for these, I discovered a loose cable hidden under my air cleaner housing (photo attached). Guess what? It plugs into the engine speed sensor (!)

This has been unplugged since before I bought the car.

The last owner sold it to as me as a parts car for the equivalent of 430 euros because every mechanic had told him his transmission needed replacing. Now that the engine speed sensor is connected properly, I have a fully functioning gearbox.

Thanks everyone for the great help!

In Antwort auf:

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This has been unplugged since before I bought the car.

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If it's true, then your car NEVER run since then? because without this enginge speed signal the engine never never never will start and you wouldn't know about transmission problems....


The one in your attachment it's the plug for the throttle... and it's not hidden under the air cleaner box - wrong attachment?

Hi Roy, it's the right attachment. I suppose its the plug for the throttle I was referring to then. It was stuffed in a void between the two rows of cylinders and just under the lip of the black plastic cover that has the Audi logo and V8 lettering on it.

The transmission has been working nicely since reconnecting whatever this is. I'm still getting some goatish revving every now and then, but that's probably another problem entirely.

I would suggest then, that the throttle pot (now reconnected) has some issues that someone tried to mask by disconnecting it.

That device gives you 3 functions.
Throttle closed (idle) switch
Wide open throttle (full throttle) switch
And
Position/angle potentiometer

A fault in mine caused erratic behaviour at 1600 rpm (I'm sure I wrote about it on this forum)
Check for-
Water ingress into the pot itself
Bad contacts at the connector

In reply to:

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The matching part numbers for outer joints are: 4A0 498 099 and 4A0 498 099D

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Anyhow, back onto topic for the time being; Tim, do you need both of these part numbers to assemble a complete CV joint? Or are these part numbers for the left and right front joints, respectively?

Thanks

Hi Jordan,

both numbers are according to the outer CV joint. You may search for both part numbers and you will find identical parts. This joints fit to RH and the LH shaft as well.