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D2 - Transmission Gearboxes, diffs, drive shafts.

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  #1  
Old 29th October 2020, 08:49 PM
Nick Jones Nick Jones is offline
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Default Autobox peculiarities

Just realised that my car has previously featured on here while belonging to Audidoody, whom it seems I bought it from.......

Anyhow, just trying to determine whether this is a fault or a feature.
I'm not an autobox connoisseur, I've owned 3 in 35 years of driving - a Dolomite Sprint that got converter to manual pronto as it was such an awful combination (BW65 3 speed clockwork slushbox that insists on changing up at 3.5k and an engine that comes on cam at 4k....) and my previous A8 - early 4.2 with the 4HP22 - which was ok, but not very subtle.

This one 2.8 FL 2WD is more subtle, but has some quirks.

1.
It's really quite hard to make a smooth getaway. It either just creeps away, or if you apply a whisker more throttle, suddenly sets off a bit harder than intended - doesn't appear to be a middle way. Not even sure if its a gearbox or throttle thing.

2.
when pottering about in traffic, it fusses about, changing gear more often than seems necessary. It's quite subtle about it and the changes themselves are fine, just seems a bit unnecessary. And sometimes, when you apply a little extra throttle it changes up a gear.

3.
It appears to alter it's behaviour and is not consistent with it's change points. Possibly it's tracking my driving and adjusting, but I don't think it does it very well. In tiptronic mode it's lovely and the changes seem even smoother - which also makes me wonder about the throttle.

The invoices say it had an oil change in 2015 ans the PO told me it had a new throttle body quite recently (also mentioned on here).

Could be it's entirely normal - a feature rather than a fault?

What thinks the panel?

Thanks

Nick
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Old 29th October 2020, 10:27 PM
ainarssems ainarssems is offline
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Default

Couple things to check:
1. Brake light switch
2. MAF
3. Vacuum leaks which could affect MAF reading.
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  #3  
Old 30th October 2020, 06:49 AM
MikkiJayne MikkiJayne is offline
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Sounds like stock 2.8 programming to me. Big Red's drives me nuts so I just keep it in S all the time.
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Old 31st October 2020, 08:22 AM
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Quote:
Originally Posted by MikkiJayne View Post
Sounds like stock 2.8 programming to me. Big Red's drives me nuts so I just keep it in S all the time.
Can you not change the TCU programming with VCDS? I have done this on my S8 so is it not a feature on the 2.8s also?
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Old 31st October 2020, 11:52 AM
Nick Jones Nick Jones is offline
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Quote:
Originally Posted by MikkiJayne View Post
Sounds like stock 2.8 programming to me. Big Red's drives me nuts so I just keep it in S all the time.
Yeah, suspected this might be the case. I'll get used to it. Probably.

On a slightly related note I had and almost new Zafira rental in Spain a couple of years ago (I actually rented a Corsa because I'm cheap, but it broke and I was "upgraded"). This had a 1.4 engine and autobox with tiptronic. Oh joy I thought, how is this unwieldy underpowered behemoth an upgrade....?

The engine was actually better than expected, but the gearbox was just woeful. It's changing habits were so erratic I presume it was broken and the tiptronic was no help as it tended to deny you gears that were perfectly reasonable, even necessary, and then immediately select them if you returned to auto mode. Hateful thing.

Nick
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Old 31st October 2020, 11:54 AM
Nick Jones Nick Jones is offline
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Quote:
Originally Posted by David's8 View Post
Can you not change the TCU programming with VCDS? I have done this on my S8 so is it not a feature on the 2.8s also?
Tell me more.... With 4 VAG cars on the drive, two of them distinctly needy, I may have to invest in the full version of VCDS....

Nick
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Old 31st October 2020, 12:05 PM
MikkiJayne MikkiJayne is offline
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Quote:
Originally Posted by David's8 View Post
Can you not change the TCU programming with VCDS? I have done this on my S8 so is it not a feature on the 2.8s also?
Only DSP on/off and tip buttons in D on/off. You can't change the shift points or target rpm range (as far as I know).
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Old 31st October 2020, 01:00 PM
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Quote:
Originally Posted by Nick Jones View Post
Tell me more.... With 4 VAG cars on the drive, two of them distinctly needy, I may have to invest in the full version of VCDS....

Nick
See this thread http://forum.a8parts.co.uk/showthread.php?t=630

There are some useful links on that thread
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Old 31st October 2020, 01:12 PM
MikkiJayne MikkiJayne is offline
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DSP is the setting that everyone likes in that thread. I'm think that is already enabled in BR based on behaviour but its worth checking. Not sure what 3 does for DSP as it's undocumented.
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Old 31st October 2020, 06:21 PM
MikkiJayne MikkiJayne is offline
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Well, to my surprise BR had DSP turned off! So, I've gone from 00001 to 00111. I didn't notice any difference on the way home from the workshop but that's only 2 miles, and it still wanted to do 1200rpm up a hill. Maybe it needs a longer journey?
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