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D2 - Engine Bay Everything under the bonnet |
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Thread Tools | Display Modes |
#11
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It wouldn't surprise me.
Once the ECU recognises the MAF is gone and gives the fault lights, the TCU seems to go into a default shift mode - if anything the gearbox shifts softer I reckon, and I drove it gently anyway knowing it wasn't working at its optimum. I have my own ideas on why these gearboxes fail, but I won't start that debate here!
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Cheers Marty ____________________ Current: 2001 Audi S8 - Brilliant Black with Black interior, C5 RS6 rims (whenever I actually put them on...), Solar Sunroof, Tinted side and rear glass, RNS-D, Grom, Bose, clunky old phone in arm rest! 2002 Audi S8 - Project Replacement head coming arrived thanks to MJ Silver with Black interior. All features as the '01, with the 'S' mode auto shifter. Dodgey rear tint (need to find a way to get rid of that). Family: 2009 Volvo XC90 V8 R Design - has a louder more obnoxious exhaust than the S8, sounds great! Love this thing - Q7 was double the price, and certainly not double the car! Sold: 1997 Audi A4 - Hamilton's Club Sport, Achat Grey (will miss the old girl) |
#12
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Quote:
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2002 D2 S8 – Ming Blue, Valcona leather, Vavona wood insert, solar sunroof (to be fitted), Heated rear seats, extended leather pack, 18” Avus, ski hatch, Bose, auto dim rear view mirror, rear blind. |
#13
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Alright David, as you insist ;-)
I doubt this is an original idea and it's based largely on what I read (and saw) on what I'm sure was this forum, where an AME (Aircraft Maintenance Engineer) partially rebuilt his own gearbox. And on talking to a gearbox expert during my recent 'scare': Most failures seem to be caused by a failure in the Clutch A Basket. Probably due in large effect to Clutch A being engaged for reverse and first gear (and I think second gear), it will be under one of the highest torque loadings of any of the baskets. I think the bearing surface on the front face of the clutch A basket is a little weak or thin (the bearing surface is like a little shim mounted in a recess on the clutch A basket surface). Over many revolutions, this bearing surface wears down to the point that the clutch A basket can move slightly back and forth on its shaft or alignment path. This in turn puts stress on an o-ring seal on the inside of the basket causing it to fail. This then results in the loss of reverse and/or first gears (and potentially second gear too I think, but it's irrelevant because by then you're in limp mode). This normally damages the clutch A basket too which requires replacement, but by the time you've gone that far in a shop, you're doing a rebuild anyway. So I'm not sure there's anything that can be done to prevent this eventual failure. There may or may not be improvements to the bearing surface in the 'improved design' baskets. I employ a strategy to attempt to maximise the gearbox's chances, and that is to change the fluid regularly to refresh the fluids consumables, such as plasticisers (to regenerate and preserve the o-rings and other rubber components), friction modifiers (improve shear strength of molecules to improve lubrication particularly under pressure), and detergents (to keep components in the transmission clean and free of contaminants). Fresh fluid on its own also provides the best possible lubrication. In this way, I attempt to minimise wear on the bearing surface of the clutch A basket as much as possible while also doing my best to protect the o-ring. Failure may still be inevitable, but at least I'll know I gave it it's best shot.
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Cheers Marty ____________________ Current: 2001 Audi S8 - Brilliant Black with Black interior, C5 RS6 rims (whenever I actually put them on...), Solar Sunroof, Tinted side and rear glass, RNS-D, Grom, Bose, clunky old phone in arm rest! 2002 Audi S8 - Project Replacement head coming arrived thanks to MJ Silver with Black interior. All features as the '01, with the 'S' mode auto shifter. Dodgey rear tint (need to find a way to get rid of that). Family: 2009 Volvo XC90 V8 R Design - has a louder more obnoxious exhaust than the S8, sounds great! Love this thing - Q7 was double the price, and certainly not double the car! Sold: 1997 Audi A4 - Hamilton's Club Sport, Achat Grey (will miss the old girl) |
#14
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Good summary
I replaced the problem bearing, carrier, and o-ring in mine as a preventative measure while the engine was out. It was actually in pretty good condition, as was everything else in there so I hope it'll manage another 100K with regular oil changes. I'm going to do the same with the FE while that's in bits too. |
#15
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I guess if you "know" (or have high confidence that's a likely cause of failure) you factor it in to the running costs, change the fluid regularly and get the box fixed at the first hint of failure.
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2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.). 2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one! Finally: gone, but not forgotten..... 1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors. e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later) 1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer. And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850! |
#16
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It does all go to show that regular servicing /fluid change is the way to go to prolong life.
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2002 D2 S8 – Ming Blue, Valcona leather, Vavona wood insert, solar sunroof (to be fitted), Heated rear seats, extended leather pack, 18” Avus, ski hatch, Bose, auto dim rear view mirror, rear blind. |
#17
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Bit of an old thread resurrection here, but I've been experiencing the same problems for a little while. My OBD started to suggest the MAF sensor & VCDS seems to have backed this up.
So, where's the best place to get a new sensor from? |
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