chris.sargent

Hi All,

I am effectively my brother's personal mechanic and he has an Audi A8, 2000 model post face-lift. He recently complained that his gearbox seemed like it wasn't quite working right. So, I told him to go get the gearbox serviced by an Audi specialist and make sure they use the right fluids and filters. Anyway, around 300 miles after he's had this service done, his transmission appears to have given up the ghost.

This is what he said about it:

"The changes were getting jerky before the service, most commonly from 2nd to 1st when pulling up at a junction etc

It didn’t really feel much better after the service, but definitely not worse either, which would suggest to me that the oil change was not a cure to an existing problem

Driving to work this morning, it basically clonked between gears especially from 3rd to 4th, 4th to 5th, with a clonking noise, then failed altogether on way home – if you pushed hard, it was like a clutch slipping in a manual car, high revs, no propulsion, then went to ‘failsafe’ mode which basically holds it in 3rd gear.

The garage who serviced the transmission said "the wet clutches have gone". They won’t take it on as doesn’t have the expertise, but drove it round the block and confirmed what I thought, basically the clutches are slipping, get no drive, then it goes into failsafe mode when the ATF gets too hot."

He has asked the garage to confirm they used Audi lubricants and they have assured him they only used genuine parts and oils. He will take it for a second opinion tomorrow and get the fault codes read (the first garage didn't, which I do find a little bit strange).

So, I'm asking, before we scrap the car or start shopping for a new transmission, can anyone explain this fault and potentially offer an explanation for the issues we have?

Many thanks everyone!

Chris

uberwgn

Chris, welcome aboard! Do you know how many miles are on the car? Had the trans ever been service before this recent attempt?

tozoM8

I would check the fluid level. It sounds like they filled it with the engine off.

chris.sargent

Hi,

To recheck the fluid was my first thought and I'm not sure if they've done it.

The car has done 121k miles but the transmission was rebuilt by VM Transmissions in the UK at 55k miles. As far as I know, it hasn't had a gearbox service since.

Chris

tozoM8

http://www.audipages.com/Tech_Articl...servicing.html

chris.sargent

Yeah, had a good read of that - it's that article that primarily prompted us to have the fluid changed. He's on vacation for 2 weeks now but when he's back I'm gonna go get the car on some ramps, check the level first, check the colour of the oil and check the diagnostics etc.

Is the genuine oil still this yellowish-green colour rather than red?

I've also read that a lot of people don't recommend an oil change on higher mileage cars... personally I don't follow this as I can't see how it can be better to run with new oil. But then, there is the 'if it ain't broke' argument.

spitanddirt

This story proves my personal mantra(again) that no one will ever care more about your stuff than you do. I could totally see this shop filling the transmission without having it running on a lift. In any case, I don't buy into the "if it ain't broke, don't fix it" attitude. Personally I find it to be an excuse for lazy people. I'm a firm believer in preventitive maintenance. My car's trans fluid was changed for the first time at 122,000 miles. All I can say is that it was nasty. I just changed it again at 152,000 miles and it looks much better. I don't use the factory transmission fluid, because it's mostly a bunch of advertising trickery and fear-mongering in order to make the average Audi driver consistently bring his or her vehicle back to the dealership for the "correct" parts.

I checked the factory fluid against multiple aftermarket lubricant manufacturers and found that MOBIL 1 Full Synthetic Transmission Fluid meets or exceeds Audi's specification for transmission fluid. In reality, it's ZF transmission who actually specifies the fluid requirement. ZF was contracted to build the transmission for this car, but also for BMW, and Mercedes Benz.

My point is that I deviated from the Bentley Service manual and used the MOBIL 1 Full Syn Trans fluid and I haven't experienced any catastophic failure. No matter how much more "stable" or "shear-resistant" synthetic lubricants are, they still can become contaminated with foreign particles and are still suseptable to vicosity breakdown. That's why you change your oil even if you think your still good. Unless you like sending your oils in for laboratory analysis every 3 months, it just makes more sense to change out lubricants at certain mileage intervals and enjoy the knowledge that all is well.

Audi(and many other vehicle manufacturers these days) only dictate that their transmission fluid is "good for the life of the vehicle" because that actually means about 7 years or 90,000 miles, AT MOST. Why? Because most people do not keep their vehicles beyond that, especially your typical Audi owner. Sure, if you car is still under warranty, then it might make sense to stick to the service/maintenance schedule to the "letter." But for a vehicle over 10 years old, you have the freedom to choose other options.

As for the transmission --- I have something that you need to consider: did the transmission starve for fluid? I ask, because when I changed out my fluid on my trans and I replaced my filter, I noticed that the pickup tube was almost completely sealed off because the oil pan had been dented upwards. Normally, I have seen grooves pressed into transmission oil pans to prevent this from happening, but since you said the transmission had been rebuild I figure this is something you should check. Depending on who or how the transmission was installed, the oil pan could have been shoved upwards. Does the transmission pan have any noticable dents or other signs of abuse?

Think of it this way: it's just like holding your hand over a vacuum cleaner hose and then removing it. The vacuum motor's whine audibly changes because you have effectly made it work harder by not allowing air into the hose - little to no air flow. Only in this case, it's only air and it doesn't lubricate the vacuum's motor. In your transmission, suction for fluid is created by the transmission front pump, and it NEEDS fluid for lubrication.

All and all it's really a toss-up on whether or not you want to spend the money to get the transmission repaired. ZF Transmission's does have a rebuilding facility here in the states. That would be your best bet. A factory rebuilt unit, but you're going to pay for it. Figure between $1800-$3500 to get this repaired.

I wish you and your brother the best of luck, that's quite a chunk of change to drop on this car. Kinda depends on how much you like the car and it's overall condition. Just my $.02

chris.sargent

Hi all, thanks for the replies - spitanddirt, I do agree with you - it was me who'd encouraged him to have it serviced in the first place!

In my experience, when something goes wrong shortly after you change something, it's normally something to do with whatever you did and best to start there first with fault finding!

I also find it no coincidence that the box should fail shortly after the service and please do remember this box has only done about 60k miles. The problems he was having before are all symptoms that would often be cured by a fluid change and service and I really don't subscribe to the 'new oil will kill it' theories that seem to come up with auto 'boxes. I really just don't understand the thinking behind it - it you had an engine that hadn't had it's oil changed for a while, I don't think anyone would leave it in!

But, OK, so I've had the A8 up on the ramps and stands this evening. The oil level is good, it is full, but the colour of the oil was not the yellowish-green colour we were expecting.

http://www.flickr.com/photos/63142815@N08/5805707288/

There is no evidence of a new filter or pan removal or any other damage to the pan, so they have only changed the oil, nothing else.

The car has only done 150 miles maximum since the oil change, but definitely does not look like oil that's new as there seems to be too much debris/sediment in the oil, although some of it could have come from the filler plug.

I've had the chance to give the car a quick drive now... basically as soon as you put your foot down the car revs with little drive, then changes up a gear at a time until finally hitting about 3rd gear... do it a few more times and it goes in to limp home mode - i.e. stuck in 4th. Driving it again in manual mode showed this slipping, accompanied by a fair bit of judder actually, in 1st, 2nd and 3rd gear but not at all in 4th or 5th gear.

Also, as soon as you reset the errors the gearbox starts working in all gears again immediately but with the slipping in the first three as before. Hence, it's not because of the 'oil overheating' that's causing the limp home. The limp home is being caused by the fact that the system is sensing there's far too much speed difference between input and output shafts and therefore there must be something wrong - the diagnostics don't seem to be able to tell anymore than that. I think at one point I read the fluid as being at 8 degrees fahranheit.

Fluid that came out still smelt sweet with no burnt smell and I'm led to believe that a slipping wet clutch will burn itself off and the oil will smell burnt. I can also understand that with a wet clutch, the viscosity of the oil must be absolutely critical for them to work as they should.

Also, I can't see how this could affect it but I'd mention it anyway, there is a (quite a bad) leak from the final drive, drive shaft oil seal. Just wondering if this was so failed that the one wheel was slipping loads and just confusing the hell out of the electronics... clutching at straws I think but you never know!

Any further advice would be greatly appreciated. My thoughts at the moment would be to do a proper service on the gearbox, drop the sump pan, change the filter and fill it with proper genuine Audi oil. If that doesn't cure it then we 'scrap' it or fit a recon box. Alternatively, has anyone ever been able to rebuild one of these things themselves or are there lots of special presses etc needed to tear it down?

Fault codes found were:

P0733 - gear 3; incorrect ratio
P0732 - similar to above, but for gear 2

tozoM8

Make sure there is no dent on the pan. I would change the filter and cut the filter pickup tube. Make it 1/2" long from the bottom of the filter.

chris.sargent

I Tozo, thanks for that. There doesn't seem to be any sort of denting or damage on the pan at all to be honest and no unusual noises.

What's the thinking behind cutting the pickup tube please?

Do you think the wrong fluid could cause the slipping clutches?