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D2 - Transmission Gearboxes, diffs, drive shafts.

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  #11  
Old 27th August 2019, 02:09 PM
ainarssems ainarssems is offline
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Quote:
Originally Posted by Dezzy View Post
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.
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  #12  
Old 27th August 2019, 02:32 PM
MikkiJayne MikkiJayne is offline
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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.
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  #13  
Old 27th August 2019, 04:12 PM
ainarssems ainarssems is offline
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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.
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  #14  
Old 28th August 2019, 08:14 PM
spannerrash spannerrash is offline
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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.
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  #15  
Old 30th August 2019, 09:13 PM
ainarssems ainarssems is offline
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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.
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Last edited by ainarssems; 30th August 2019 at 09:53 PM.
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  #16  
Old 30th August 2019, 09:40 PM
ainarssems ainarssems is offline
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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.
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2006 A8 Sport 4.2TDI quattro SOLD,
1997 S8, reached end of life with gearbox failure

Last edited by ainarssems; 30th August 2019 at 09:54 PM.
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  #17  
Old 30th August 2019, 09:44 PM
MikkiJayne MikkiJayne is offline
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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.

Last edited by MikkiJayne; 30th August 2019 at 09:47 PM.
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  #18  
Old 30th August 2019, 10:02 PM
ainarssems ainarssems is offline
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Quote:
Originally Posted by MikkiJayne View Post
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.
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2006 A8 Sport 4.2TDI quattro SOLD,
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  #19  
Old 31st August 2019, 06:37 AM
spannerrash spannerrash is offline
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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.
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  #20  
Old 4th September 2019, 02:58 PM
ainarssems ainarssems is offline
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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.
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2011 Q7 S Line 3.0TDI, 2016 Tesla Model S 90D

8 history:
2006 A8 Sport 4.2TDI quattro SOLD,
1997 S8, reached end of life with gearbox failure

Last edited by ainarssems; 4th September 2019 at 03:00 PM.
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