drmotorsport Posted May 2, 2006 Report Share Posted May 2, 2006 In my lurking around TSN and other fine Audi sites i've seen many tales of woe of the gearbox hunting problem, the solution being either replace the gearbox or keep replacing the fluid. I don't recall ever seeing a cause for the problem. Buried in ELSAwin i've just found the stuff below - hope this helps someone and it shows that Audi are aware of a problem... Technical solution Problem description Vehicle jerks at 1200-1600 rpm during the torque converter control phase. Cause Because of a missing water drain valve in the plenum chamber below the air conditioning unit water runs out onto the gearbox housing below. The water can get through the gearbox ventilation into the ATF caus-ing running problems. Production solution Extra clip on the water drain valve from 25.09.2000, Chassis No. 4D 1N 004497 Service solution Check the ATF. If it is very milky, the gearbox must be replaced. If the water content is below 0.5%, change the ATF twice. Then drive the vehicle for about 3 to 6 miles after every change. The oil pipes and the gear oil cooler must be carefully cleaned. If the water drain valve is missing in the plenum chamber (above the gearbox housing in the body), it must be fitted. Bond the drain valve to ensure its permanent attachment. Before fitting the rubber valve in the cut-out of the plenum chamber clean the contact surfaces and then bond the rubber valve with universal bonder D 001 200. Accounting instructions Service number/damage code/manufacturer: 5155 018 ... Link to comment Share on other sites More sharing options...
nikw Posted May 2, 2006 Report Share Posted May 2, 2006 Interesting find! I don't recall seeing any milky fluid in the various pics posted or the cars I have personally worked on, but sorting that drain valve out has to be a worthwhile piece of preventative work, nonetheless. Excuse me, I've suddenly got something new to fiddle with on my car... Link to comment Share on other sites More sharing options...
thraxtos Posted May 13, 2006 Report Share Posted May 13, 2006 Is this only on Audi or could it be on BMW also - Some of the BMW 6 Speed boxes (X5 Diesel & 530 Diesel) are also shared (ZF) with Jaguar on S-type which all give gearchange problems ....... ??????? Link to comment Share on other sites More sharing options...
drmotorsport Posted May 13, 2006 Author Report Share Posted May 13, 2006 Having had a BMW 735 before, the gearbox is supposed to be sealed for life like the Audi's - but in the real world there are also stories of boxes breaking - the solution - also change the fluid. Link to comment Share on other sites More sharing options...
SneakyMcC Posted May 14, 2006 Report Share Posted May 14, 2006 Thats very is very interesting. I wonder if further explanation from Audi is called for? Link to comment Share on other sites More sharing options...
cruiser647 Posted May 15, 2006 Report Share Posted May 15, 2006 There is an A8 on eBay with a 'broken' gearbox. 4.2 Q Sport in Perth. The gearbox is in constant Limp mode apparently. So could be fluid, duff Maf, duff gearbox or just a simple code reset. A8 with Duff Gearbox Link to comment Share on other sites More sharing options...
nikw Posted May 15, 2006 Report Share Posted May 15, 2006 <Paging Mr Botang...> Link to comment Share on other sites More sharing options...
gapthree Posted May 15, 2006 Report Share Posted May 15, 2006 Took my A8 4.2S to Chester Auto Gearboxes (01244 537070) where for £160 inc VAT they drained ALL the oil out,flushed it and refilled with Audi oil and a new filter. Gbox much smoother again. They have a device to pump / suck ALL the oil out of the torque convertor. Previousley I've spent £300 with Audi doing 2 drains of around half the fluid after a filter and strainer change. Interestingly I pointed out the advice from Audi that the Oil in the box is life long. They simply asked why does Audi's oil come marked up with a dated 12 month shelf life then? They recommended a yearly fluid change to ensure smooth running and spot any problems early before they become expensive by checking for metal and contaminents in the fluid. Makes sense to me with 152K on the clock. They charge around £450 to remove / refit the box and then its parts and labour dependant on the fault. Thought you should know. Link to comment Share on other sites More sharing options...
Ska Posted May 15, 2006 Report Share Posted May 15, 2006 and then what about this? Is this the shunting that we all talk about: 2.8 3.7 4.2 97/99 Engine jolts in driving direction at low engine speeds Replacement gearbox control unit (100 927 156...) with higher-set converter clutch regulation and traction shift-up set for higher speeds from 4th to 5th gear. See API 5/98. 90% because if it is the TCU cost £850+ VAT Link to comment Share on other sites More sharing options...
Botang Posted May 15, 2006 Report Share Posted May 15, 2006 [ QUOTE ] <Paging Mr Botang...> [/ QUOTE ] Nah its not worth it, its going for over £1k and it has 200,000 miles anyway. I'll keep my spare engine and gearbox incase I have any accidents with the new hairdrier Link to comment Share on other sites More sharing options...
nikw Posted May 16, 2006 Report Share Posted May 16, 2006 @Ska: Ah ha! That sounds like a proper fix for the shunt/thump which occurs at 40-50mph on a closed throttle. Changing the revs at which the torque convertor locks and unlocks would make sense. What I want to know now is (1) where did that come from and (2) can we get the gearbox control unit replaced at reduced/zero cost as it seems to be an inherent (i.e. designed-in) fault? Link to comment Share on other sites More sharing options...
Ska Posted May 16, 2006 Report Share Posted May 16, 2006 It came from the Elsawin data base, in the section as the the other fix. Its as if they have logged the complaints, so they know there is a design fault and just hoped that when and if a customer has this fault they'll charge them for this fix I would love it for them to replace the TCU for free but at £1000 a pop retail price covering 97-99 models do you think they'll do that for cars that are now 9 years old. Looks like they've fixed this for cars on 2000 plates; would be interesting to hear from any 2000+ A8 owners if they had these dreaded symptoms. Another point 2nd hand TCU's could set you back from anywhere between £50-£200ish if anyone hears of a dead 8 in a scrapy then they should let the folks on TSN know, unfortunately this might be the only recourse Link to comment Share on other sites More sharing options...
nikw Posted May 16, 2006 Report Share Posted May 16, 2006 Unfortunately I suspect that you are absolutely right about the fix - why admit to a problem when your dealers can earn £££s to rectify it? Despite asking once or twice in the past I've not had any feedback from facelift D2 owners regarding this. The only facelift car I have direct experience of is low mileage and was still behaving perfectly before we changed the fluid as a preventative measure. The fact that it is an S8 also has a bearing because the shorter 4th & 5th gear ratios keep the revs that bit higher at the critical 40-50mph. Any facelift owners care to comment? In particular I'd love to hear BumpRT's before/after gearbox experiences. Link to comment Share on other sites More sharing options...
Ska Posted May 16, 2006 Report Share Posted May 16, 2006 Wheres this valve that drmnotorsport talks about and what exactly the Plenum chamber? Is that the black box with the ecu and tcu in it and how the phuck do you remove it cos the picis in elsa win may well have been drawn by my 5 year old Link to comment Share on other sites More sharing options...
drmotorsport Posted May 16, 2006 Author Report Share Posted May 16, 2006 my S8 is a facelift (just) and has had it's gearbox replaced. Previous owner suddenly lost reverse gear altogether at about 100k miles - but got it replaced under warranty. Link to comment Share on other sites More sharing options...
Ska Posted May 16, 2006 Report Share Posted May 16, 2006 Didn't BumpRT's car loose the reverse gear as well? Link to comment Share on other sites More sharing options...
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