Depressed A8 owner - Warwickshire - Page 4

Chris.sargent · #31 6th June 2011, 11:02 PM

So 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?

Chris.sargent · #32 6th June 2011, 11:13 PM

Quote:

Originally Posted by Conan_the_Librarian

Remember that unless they have one of the special machines that cycles the new ATF into the box as it drains the old ATF there is quite a bit left in. Draining only leaves 2 to 3 liters in the TC and valve bodies. Not changing the filters is a false economy as the filters filter! Therefore it will slowly clog up. Did you ask for an ATF and filter change? If so then back to the garage I would say. If only a fluid change was requested then you have probably got what you asked for.

Given the colour of the ATF now only analysis of it would detect if it was the wrong fluid.

Hey Conan, I know what you're getting at - the ATF would come out a bit dirtier if they didn't either use one of those machines or drop the pan and completely empty the box. Hence the 'new oil' might come out looking a bit dirty as we found.

Anyone know if the genuine oil is still the yellowish green colour?

Singh · #33 7th June 2011, 12:47 AM

Whoever quoted you £1,000 labour to change the gearbox probably doesn't have a clue. I paid £250 and it was in and out in four hours. That was with Ben who can do it quickly being familiar with these cars. The most you should pay is £600, I wouldn't pay more then £350 for a reconditioned gearbox either unless it was freshley rebuilt. No one here has rebuilt one but Tozo on quattroworld is a ZF gearbox god, he has refurbished loads and even converted 2 D2 S8 models into 6 speed twin turbo manuals, we need him in the UK!
If your seriously considering getting rid, I could be interested as a project car. Also, I have heard very good things by friends about OSC Motorsport in Rugby, may want to speak to them.

Conan_the_Librarian · #34 7th June 2011, 06:53 AM

Quote:

Originally Posted by sarg

I think that's a bit unfair Conan.

I asked for a gearbox oil service, I also visited the garage prior to booking in for reassurance that they knew what they were doing as I knew rnough to know it was critical to be done correctly.

However, I am not a mechanic, far from it, and do not have the knowledge to say to them, you know what, best make sure you change the filter and this and that and everything else too, that's why I employ a garage!

Bill, A8 parts reckon about £700 for a 2nd hand box, plus best part of £1,000 for somebody to fit it - I can get a warranted recon box fitted for £1860 plus VAT (Automatic Transmissions, Huddersfield), so I think the recon box would be the best option if I decide not to scrap.

However, I also saw A8s on Ebay for spares or repair for about £1,200, so it might be better just to cut loose, I haven't decided, but I know what you mean - spend 2k ish, get my favourite ever car back, but what is next? 120k miles, how long before the engine lands me a big bill, or an exhaust, or some more suspension bits, all getting a bit expensive now, though the attraction is still there for me, it is a great car with a nice spec.

Just playing devils advocate - Sorry.

Quote:

Originally Posted by Chris.sargent

So 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?

Final drive first. There are 2 on the box. Rear output, which is indicated by the smell of burning oil as it drips onto the passenger side cat. and front outputs. Neither are lubricated by the ATF as they are separate from the transmission and each other. They use final drive oil and the output seals are easy, if time-consuming, to change.

Transmission. Do you get any noise when the car starts, this could be cavitation, where the filter is blocked and the ATF can not be sucked up quick enough by the pump which is running at engine speed. I cured this with a filter and ATF change. 8 deg F is way wrong. it needs to be at 30 deg C for level setting during the fill, and will climb from there.

Next possibility is that the valve bodies are malfunctioning. Have a read of this post for more information. The transmission sticky also has loads of information. There was also a post on Tyresmoke in the A/S8 section by someone who did a valve body service, but I can't find it at the moment. He found that several of the solenoids had mesh filter screens and they quite fouled up with gunge.

Slipping clutches are the most common failure. Rebuilding is more fiddley than difficult. All the parts are available from ZF and I for one would like to have a go when I have time. There is a guy in North Yorks that service the HP25 for free!!!! But he does Land and Rangerover versions. There are however a couple of special tools needed.

Quote:

Originally Posted by Chris.sargent

Hey Conan, I know what you're getting at - the ATF would come out a bit dirtier if they didn't either use one of those machines or drop the pan and completely empty the box. Hence the 'new oil' might come out looking a bit dirty as we found.

Anyone know if the genuine oil is still the yellowish-green colour?

Yep. Part number G052162A2. Don't pay more than £8 a litre. You can get it here at £7.27 + delivery.

A full ATF and filter change (don't forget the 'O' seal) will cost about £120 tops in parts alone. The ATF is available in bulk of 20Ltrs to save money. Sell the left over on to someone on here.

Chris.sargent · #35 7th June 2011, 10:22 AM

Should have said 84 degrees, not 8, sorry!

Chris.sargent · #36 7th June 2011, 11:30 AM

Quote:

Originally Posted by Conan_the_Librarian

Final drive first. There are 2 on the box. Rear output, which is indicated by the smell of burning oil as it drips onto the passenger side cat. and front outputs. Neither are lubricated by the ATF as they are separate from the transmission and each other. They use final drive oil and the output seals are easy, if time-consuming, to change.

Hey Conan, I mean the rear final drive on the rear axle, not the one from the autobox. The autobox one had it's output shaft seal changed recently as yes, it was dripping on to the left cat. The rear final drive is leaking from the n/s driveshaft seal.

Quote:

Originally Posted by Conan_the_Librarian

Transmission. Do you get any noise when the car starts, this could be cavitation, where the filter is blocked and the ATF can not be sucked up quick enough by the pump which is running at engine speed. I cured this with a filter and ATF change. 8 deg F is way wrong. it needs to be at 30 deg C for level setting during the fill, and will climb from there.

Yeah, sorry - typo from me! Was 84 degrees I think. No strange noises at all - even under the car with my head just a few inches from the transmission with the engine running!

Quote:

Originally Posted by Conan_the_Librarian

Next possibility is that the valve bodies are malfunctioning. Have a read of this post for more information. The transmission sticky also has loads of information. There was also a post on Tyresmoke in the A/S8 section by someone who did a valve body service, but I can't find it at the moment. He found that several of the solenoids had mesh filter screens and they quite fouled up with gunge.

I will have a read and look in to it. Anyway of checking the valve body operation without stripping it down? Will they throw fault codes? Will the valve body failure or blocked mesh filters cause these sorts of faults?

Quote:

Originally Posted by Conan_the_Librarian

Slipping clutches are the most common failure. Rebuilding is more fiddley than difficult. All the parts are available from ZF and I for one would like to have a go when I have time. There is a guy in North Yorks that service the HP25 for free!!!! But he does Land and Rangerover versions. There are however a couple of special tools needed.

I'm pretty sure the clutches are slipping - the question is why? Is it because they're just totally worn out or is it because they've got the wrong fluid in? Also, does anyone know if there's any form of friction modifier that could be added to help stop the clutches slipping? Also, it still seems strange to me that they would 'fail' almost immediately after the fluid was changed and that seemingly all of them failing on 1, 2 and 3rd gears at the same time?!

Quote:

Originally Posted by Conan_the_Librarian

Yep. Part number G052162A2. Don't pay more than £8 a litre. You can get it here at £7.27 + delivery.

A full ATF and filter change (don't forget the 'O' seal) will cost about £120 tops in parts alone. The ATF is available in bulk of 20Ltrs to save money. Sell the left over on to someone on here.

Is it worth changing the fluids and filters at this point?

Conan_the_Librarian · #37 7th June 2011, 11:57 AM

Quote:

Originally Posted by Chris.sargent

Hey Conan, I mean the rear final drive on the rear axle, not the one from the autobox. The autobox one had it's output shaft seal changed recently as yes, it was dripping on to the left cat. The rear final drive is leaking from the n/s driveshaft seal.

Yeah, sorry - typo from me! Was 84 degrees I think. No strange noises at all - even under the car with my head just a few inches from the transmission with the engine running!

I will have a read and look in to it. Anyway of checking the valve body operation without stripping it down? Will they throw fault codes? Will the valve body failure or blocked mesh filters cause these sorts of faults?

I'm pretty sure the clutches are slipping - the question is why? Is it because they're just totally worn out or is it because they've got the wrong fluid in? Also, does anyone know if there's any form of friction modifier that could be added to help stop the clutches slipping? Also, it still seems strange to me that they would 'fail' almost immediately after the fluid was changed and that seemingly all of them failing on 1, 2 and 3rd gears at the same time?!

Is it worth changing the fluids and filters at this point?

Rear final drive won't affect the tranny. Process is similar to front.

84 deg, Phew!

No way to test valve body in the car apart from the output tests on VCDS. You may need a genuine lead to do this though. It activates the shift solenoids etc and if they throw a fault records it in the fault table I think.

If I were in doubt about the fluid, and you know the filter wasn't changed then I would change both as a DIY option before commiting to more expensive lines of action.

Adrian E · #38 7th June 2011, 12:38 PM

when my transmission oil was changed, with filter, 7 litres of fluid went back in which given the capacity is about 9 litres is pretty much all you can expect to get out without draining the torque converter.

If the fluid appears wrong type you might want to flush with fresh fluid and change again - but that's not a cheap option! I'm aiming to have my fluid changed again in 2 years (will be about 10k miles) which should get some more of the old stuff out.

ainarssems · #39 7th June 2011, 01:51 PM

Quote:

I'm pretty sure the clutches are slipping - the question is why? Is it because they're just totally worn out or is it because they've got the wrong fluid in? Also, does anyone know if there's any form of friction modifier that could be added to help stop the clutches slipping? Also, it still seems strange to me that they would 'fail' almost immediately after the fluid was changed and that seemingly all of them failing on 1, 2 and 3rd gears at the same time?!

Clutches would be slipping because they are worn out or if there is not sufficient oil pressure to press them together. Fresh oil could have lifted old dirt up and blocked filters or caused sticking solenoids not closing or opening properly.

Quote:

when my transmission oil was changed, with filter, 7 litres of fluid went back in which given the capacity is about 9 litres is pretty much all you can expect to get out without draining the torque converter

Just taking sump off will get You around 5l out.

Proper oil change takes 11-12l. After initial fill-up before starting car they connect pump/meter between oil radiator and gearbox in return pipe and this device collects dirty oil running from gearbox through the radiator and then pumps the same quantity of fresh oil until returning oil is seen clear either in clear hose or window. After that they reconnect the pipes , warm up gearbox and check final fluid level.

Chris.sargent · #40 8th June 2011, 01:26 PM

Popped in to Revo Technik yesterday and told them what happened. They immediately asked 'what type of oil did they put in and is it full?' We showed them a sample of the oil we'd taken out, which is red and quite thin and again they immediately said it was totally the wrong oil, wrong colour and far too thin and watery. Explained that we might be able to save the box my doing a couple of full flushes and filter changes.

So next step is to contact the original garage who assured us they did it all properly and 'absolutely' used genuine Audi 'box oil - even listed the Audi part number on the invoice. Clearly they haven't so we will be asking for a refund, inconvenience compensation and that we will send a bill to them for a rebuilt box if we can't get this one going. Very frustrating when the guy supposedly worked for Audi for 20 years before setting up on his own (and this is the not the best sorts of things to be doing for your reputation when you're just starting out!) and assuring us he would do it right - we knew how sensitive these boxes were before doing it!

Depending on what they say and how they react, we may ask them to put it right or we just do it ourselves properly so we know it's been done to our standards!

Will update in a few days hopefully....