Not looking good
 

Unless it's "just" the F125 switch.....

Argh :( That's usually something slipping, and that is usually the front broken off the front clutch drum.

Assuming you don't fancy a full rebuild, replacing the clutch drum is DIY'able if you're able to get the gearbox out. Its available new from ZF dealers, or you could use a donor gearbox, although that's a risk that it also has a cracked drum. Prestige have a dead one in at the moment I think, although I don't recall what the fault was.

Problem appears to be with 1st gear. Moving off it makes a jolt and switches to 5th. If I manage to manually switch to 2nd before fault occurs it works fine until goes in 1st again.

Any idea what the solenoid current should be? Most are 0.144A but one is 0.742A?

Also strange that fault code says Gear 3 but problem seem to be with 1st.

Unfortunately no time and no facilities to DIY it if the box need to come off, and not worth paying someone else to do it as car when working was worth £1k at most. I did replace clutch and flywheel on A6 on the drive but car was just high enough to disconnect the box not to actually remove it from under car.

Unless it's a solenoid or something else I can DIY from under the car without removing the box I am afraid it will be the end of S8.

This is what Elsa say




http://forum.a8parts.co.uk/attachmen...1&d=1566667251

http://forum.a8parts.co.uk/attachmen...1&d=1566667251

As soon as I move off, jolt and fault code registered for gear 3 when it's only been in 1st, if I manage to get to 2nd all other gears work fine including 3rd until it selects 1st again. :Confused::Confused::Confused:

Ffs ainars, must be save able on a shoe string.
Just out of interest what happens when the 4 speed is coupled to the S?

I do not have a lift and don't fancy handling 150kg gearbox on the drive lying under car, even manual box with half a weight was a bit of struggle. Paying someone else blows the shoe string budget straight away just removing and refitting without doing anything to the box.

Don't know about 4 speed but would need at least box, rear diff and TCU and shifter not realy worth trying unless already had a donor car.


I need to do a bit more testing and research to see if it's worth draining oil and removing pan to have a look inside. I don't understand why is it showing fault code for gear 3 just as you start moving off in the 1st. Also it should go in 4th not 5th as it does in limp mode. just need to study behaviour and have a best guess at what is the most likely fault which will then determine if it's worth poking around without removing box. I guess it would not hurt to at least check oil level but as it seems to work fine in 5th oil is probably OK.

The 5HP24 service manual has some details of the clutch operation logic so you can see which clutches are enabled in which gears etc. Might be worth starting there to see if you can see why its behaving like that.

Also, I noticed that in the S8 limp mode is 5th, rather than 4th which is normally cited - could be because the S8 gearing is lower? Limp is a mechanical feature though so not sure how the A8 and S8 could be different if that is the case.

There's a chance it could be the valve body. The Americans have a pressure valve mod that they do when the box starts misbehaving whereas we tend not to get involved in that sort of detail (throw it away or full rebuild). Might be worth reading up on that to see if it's related.

Are you able / inclined to pull the gearbox sump on the driveway? Shiny chunks in the sump is the ultimate diagnosis of a broken clutch drum. If there's nothing untoward in the sump it may be valve body related.

I can drop the sump but want gather more intel first, don't want to pull sump if it's hopeless as I think exhaust is in the way and at the moment car still drives so if I was to sell car as is then it would be possible for buyer to drive it away. If I drop the sump it will need new gasket and oil to make it move. On the other hand if I take the wheels and battery off and scrap the shell I will probably get the same kind of money as selling the whole car.

I think the valve MikkiJayne is referring to is the Transgo valve. It's a pressure regulator valve that fits into the front lower valve body. It uses fibre seals that are supposed to help with hard shifting and reduce the risk of the pressure spike that damages the A clutch drum.

It's recommended as a preventative measure though and will not fix a box that is already damaged.

I agree with what you say though. Calm down, take some time and gather the evidence before jumping in too deep. We all know the fragile nature of these boxes and it may well be that it is goosed, but unless your in a rush don't rush into anything.

On a recent service of my box I found lots of contamination on the magnets. This is a sign that all is not well. I took a couple of days to think over what to do and then just decided to let things play out and see what happens.

These gearboxes really are the achilles heel of these cars.

I have been reading a lot online about 5HP24 and I am none the wiser. It still looks to me that it is more likely major mechanical issue that needs gearbox to come off for repairs. I will do some driving and logging early Saturday morning while there is not much traffic to interfere and it's cooler so that not to overheat box with torque converter slipping in 5th.

On my journeys I have discovered this place https://www.planetgearsuk.com not far from me which offer some other 5HP24 boxes like in BMW and Land Rover for as little as £350 to rebuild of box +cost of parts required or sell reconditioned boxes for under £900 https://www.ebay.co.uk/itm/RANGE-ROV...IAAOSwVvRbK5IP. Have not seen any bad reviews but a number of positive with quoted costs about £1k for remove, repair, refit, which would be just about my upper limit. So after I gather more data I might send them details and see what they say.

Online car scrapping places offer anything from £150-500 for the car that is able to get on recovery track under it's own power. If I drive it to scrap yard myself best I can get is £200 for the shell and can take take off whatever I want. £300+ wheels + tyres, £40-50 battery, cats for recycling £200+ before I take off anything else. Or I could take off whatever I want at home and scrap yard come to collect shell with whatever is left for £60.

That's remarkably inexpensive. I shall be interested to hear what they say +++

Have you spoken to Prestige? There are only 27 PF S8s left now so they might be interested in it, especially if you could get it there. Better they recycle it than it get crushed by a random scrapyard.

No I have not but I cannot see them being that interested, I might drop them an email but between me driving it there, my time and return journey cost I think I would want at least £700 and I just don't see them paying it.

I would be surprised if they didn't pay at least £700 for it. These engines alone usually sell for more than that and then the rest is profit. Of course you need to figure in the labour involved in stripping the car but I can still see a profit at that price.

It's always difficult to consider breaking one of these cars but at least with companies like a8parts on the case other owners may be able to keep their cars running.

It will be interesting to see if they make you an offer.

Didn't get chance to test on Saturday but have done some driving around today.

There are some bad news and good news.

Bad news are that it's 1st, 2nd and 3rd affected not just 1st and it comes up with 17117 and 17114 fault codes, so that would point to fault with A drum.

Good news is that it is intermittent so I think it is less likely to be major mechanical failure, more like something sticking.

Moving off in 1st almost always slips. If I put it in Tiptronic move off slowly and do not switch over manually I can see it slipping, switching to 2nd, sometimes slipping in 2nd, sometimes not. If slipping in 2nd it switches to 3rd, if slipping in 3rd it switches to 4th and never slipping in 4th or 5th. Then if I manually switch back to lower gears they are usually fine and not slipping even with heavy throttle as much as I can push without activating kickdown. And it keeps working fine and not slipping in any gears not even in 1st. But if I come to standstill like at the junction it will slip again in 1st. If downshifting hard with high revs it does make a noise, possibly sucking in air if oil level is off. So I think before I do anything else I will need to check oil level, hopefully Friday or Saturday. The problem is to get under car and to keep it level to check oil level and by the time I get to somewhere with a lift oil will be too hot.

I am hoping this is the issue, it says from ZF manual overevving when starting from stop which implies it could be slipping when moving off but be fine afterwards which is what I am experiencing, plus the valve chatter could be the noise I hear on downshifts.

http://forum.a8parts.co.uk/attachmen...1&d=1567607804

That's sort of positive then. Do you have access to the gearbox filling tool?

Nothing that cannot be DIY'd.

A bottle, hose and a bend piece of pipe. The idea is to use pressurised garden spray bottle with a bent piece of brake pipe attached, it's harder to get it lifted and level.

Fingers crossed that this is the problem! What a great result that would be after your fears that the box was toast.

Well have not done anything yet, I guess I just keep finding excuses to delay bad news just in case if it's not oil level. :ROFL: Also having 3 cars and never needing more than 2 at the same time reduces the urgency. I's been the same in the past with only 1 car out of action things move pretty slowly but if I am down to one fully working car things start happening a lot faster.:)

Looks like some 5HP24 boxes came with dipstick to check level and at least some could be retrofitted with it. I wonder if we could do it on A/S8

http://www.meurosport.com/5HP24_Dip_Stick.php

With me being lazy bugger and probably not able to get the car lifted and level on the drive for the proper level check I think I will just disconnect cooler line by the radiator and pump in 1-1.5l of ATF and see if it changes anything. If that helps then I can proceed to proper level check and possibly fluid/filter change.

I recall asking the designer ages ago about that and IIRC the answer was: only if you're in the USA and come to me to get it fitted as the prototype.

So I filled about 1.2-1.3l of oil in the box through radiator pipe but no improvement. :( If anything it's worse now, could be fault developing further or the new oil has introduced more lubricity so it's slipping easier. It's slipping in 4th as well now and it's less often that I can get all gears to work OK and when they work kind of OK it's only for a short time before they start slipping again, I think it was probably slipping in 4th before as well I just did not feel but now it's more pronounced. 5th still working fine. After some more research I found out that the default failsafe mode for the box is 4th but if there is a problem with forth it goes to 5th. And if it goes to 5th in failsafe it's usually issue with A clutch, either broken drum or no oil pressure.

Interesting fact on Audi oil container it says that if stored in sealed container it can be used for 3 years since date of manufacture, but when filled in box it's good for life :ROFL:

Sent e-mail to Planet Gears in Peterborough this morning an the chap called me back said he was sorry about delay in calling me back as he was travelling to their London branch today, going from the phone number he was calling from https://reengineeredtransmissions.co.uk/ He was not going to speculate what was wrong and how much it will cost to repair but as an example he gave me some prices.

1.Remove box, half rebuild, refit, new filter and oil about £900-950 +VAT.
2.With a full rebuild less valve body around £1400+VAT
3.If there is something wrong with valve body it's £150-350, he did not specify and I did not ask but I guess +VAT

I asked what's the difference between half and full rebuilt, he said half rebuild includes all soft parts, full rebuild includes all wear parts.

I did forgot to ask about torque converter but I guess that's not included.

Not sure about next step but I guess changing oil and filter will probably be waste of time and money although oil can be had pretty cheaply https://www.ebay.de/itm/20-Liter-Aut...item54742d0d55

This is sounding very similar to my fault a few years ago, where the car remained driveable, but kept slipping into limp mode under anything but light throttle, with an incorrect gear ratio code.

Turned out to be a broken pipe from the valve body to one of the clutch packs.
Gearbox specialist diagnosed it and it only cost A$350 or $450 or something to repair.

Wishful thinking perhaps, but you never know your luck. The fact that it keeps driving is something.

Oh no... sorry to read about this :-(

If you have space and love the car maybe to buy a second used gearbox and swap? Can be cheaper than fixing existing one, leaving it for some time in the future to fix. When the second gearbox fails swap again for the fixed one.

There is a guy on YouTube (Gary Ferraro) who re-builds zf transmissions including the 5hp24 fit to our cars.

It may be worth checking out his channel if you haven't already. He does a section on common faults and, if I remember correctly, he mentions the little steel pipe that is prone to breaking.

I can't remember exactly but he may even go into what the symptoms are when this happens.

Fingers crossed it's something cheap.

Cheers Frank

Don't think it's wise to get used gearbox considering how often they fail, not sure if there is one available with the correct code anyway. It's either repair or sell the car.

Anyway have been busy with A6, suspension arm failed last Friday.

http://forum.a8parts.co.uk/attachmen...1&d=1568730838

Wow! Never seen one do that before :eek:

Did it do that on the move?

Was reversing and turning out of the drive when it dropped. Was considering getting taxi to nearest ECP get the part, axle stands and tools and fix it myself. But choose to do emergency join AA. AA guy by the looks did not want to do anything and just called recovery truck, said he could net get part locally but both GFS and ECP were showing them in stock in both Coventry and Leicester ( I was in Lutterworth area). I wish I had gone the taxi to ECP way.

There was no other damage initially but moving it on and off the truck chewed up wheel arch liner, damaged wing and tyre. He was not able to drop it in font of my hose due to other parked cars and when I tried to move car couple of meters forward driveshaft tripod popped out as it was too stretched. Also after about and hour noticed puddle under opposite corner, brake caliper was leaking, they must have disturbed it when strapping car to truck. When I changed caliper I decided it's a good idea to change the hose as well and the pipe cracked as it was too rusty.

This was original almost 19 years old arm, still has date stapms on rubber bushes from 2000 and done 232k miles.

Goodbye to S8
 

Well the S8 went to forum sponsors Wednesday morning, I kept the alloys putting £30 16" set from A4 bought locally on the car to get it rolling on and off the trailer and cut out cats and sold elsewhere as part of the deal.

I bought car cheaply in May 2008 but previous keeper did not send the log book off and I was not bothered to get it until insurance company requested a copy of it so officially it's been registered in my name since October 2009. Looking at what I paid for it and how much I got for the car, cats and adding the value of alloys I kept it's only cost me less than £10/month in depreciation over last 11.5 years.

Initially I was going to sell cats to https://www.catalyticconverterrecycling.com/ as they offered £340-350 and they have home pick up in checkout but even with me choosing home pick up they wanted me to post them to Malaysia so they were sold to my mates guy for £280 who buys them in large quantities, cuts out cores and sends them in bulk for processing to Lithuania and gets paid for the metals recovered minus processing costs.

So I am 8less now but will still be lurking the forum and while I do not have any plans to buy another 8 in near future you never know. I did kind of consider 4.2TDI D3 couple of years ago but I have lost any interest in D3 and anything newer does not seem any tempting apart from matrix LED and laser headlights and is too expensive. You never know if I stumble across cheap 4.2 D2 with LPG I might just buy it. :)

A sad end, but at at least it will help others keep going. Hopefully you will be back in a D2 eventually :)

Welcome to 8less club.
I'm still undecided where I want to go.
After D2 I hate everything.

So what do you drive these days? Do you have a stop gap car, drive wife's car or take a bus?:)

I still have C5 A6 2.5 TDi quattro Sport which is technically wife's but I mostly use it and a B6 S4 Cabriolet which is technically mine but wife mostly uses it.:) So I don't really need another car any time soon. I have kind of been looking at C6 and B6/7 Allroads but wife wants Q7.

We have wife’s 2017 A3 with ACC.
Very fine car, but not something to love and cherish.
Also have Fiat Grande Punto 2007 beater car that receives minimum maintenance.
These two cover transportation need.
We don’t drive long distance.
I work 90% from home. No commute.

Want large barge for long family trips, but still undecided what I want.
S8, Cayenne, Q7, A6 Allroad are all good candidates.
But nothing that really drives me towards parting with money :)
After D2 they all look crap.