Gearbox service by ZF in Dortmund

[Architex_mA8tey]

Originally Posted by Ian@A8Parts

We are noticing (apart from the S8's) that the facelift gearboxes seem to last longer. We are thinking it may be due to the electronic throttle, which noticably backs off the engine during a gear change - Something that the pre facelift did not.... This is one of Davids theorys as hes very much pedal to the metal, and notices every split second that he's not on 'full throttle'... Since moving from a pre facelift to a post facelift, he's noticed this 'backing off' behaviour....

Im just wondering if that is the case then perhaps all us facelifter's should be driving in full auto mode where possible rather than tiptronic mode to help preserve our boxes longer? If what you say is true Ian then it would seem like staying in auto would mean the electronic throttle does it's stuff wheras in tiptronic presumably its not likely to?

I've noticed with my box now, after having the "A-Drum" replaced by VMT and then a solenoid replaced, the gearchange is now smoother than it's been for a long time, particularly in the morning when it's cold, there is no longer a lunge into gear from cold start.

However, I still don't trust it. It does funny things now and then, like changing down at odd times and in particular it does this one thing at high speed under full throttle whereby it misses a beat, like it wants to change down but in a split second decides not to. Usually this happens above the 4k rpm mark at full throttle in top gear, in D or S.

Also, there was one time it definitely went to change down from 4th, spent about a half second thinking about it then decided to stay in 4th for a few seconds, then changed down to 3rd smoothly. Hard to explain really, there's no jerking, it's like a manual clutch slipping very slightly before it either stays in gear or changes down.

I've decided I'm going to give it a few months still to settle down after the recent jobs, then re-assess what I'm going to do with it. I wish there was a manual conversion option, as it would be a fantastic motor and more economical with a manual gearbox, but ah well - we'll see how we get on

[Conan_the_Librarian]

Originally Posted by jmw748

Ian,

If I'm reconditioning my gearbox fully, should I still look to sell my beloved S8 soon? She's already had a pre-emptive gearbox service (for what benefit?), a new windscreen, wheels are being refurbed Tuesday and I'll book her in for a cambelt change next month. I'm not going to keep ploughing thousands into the car - I would rather consider converting it to manual instead or just cutting my losses soon. I talked to Unit 20 about a manual upgrade after hearing a rumour they'd done so to an RS6, but it turns out they haven't done the transplant yet and they push their auto issues to CAT, so no real experience of the conversion yet. As much as I love the S8, there's a fine line between dedication and commitment to a marque and foolhardy investment. At least I don't have a multitronic box (reading horror stories about those makes me wonder if Audi are any use at picking the best auto boxes). When I looked at getting a motorway muncher, I thought twice about high mileage 5 Series' because they have auto problems - turns out they use ZF boxes too!
If Chester Auto Trans replace the torque converter, friction plates etc, should I expect the box to last for a good period after the job?

If it were me facing a tranny reconditioning I would find out what the guarantee was first. Just having components replaced means that something else may go wrong. A 'full' reconditioning to as-new means that the warranty should cover all eventualities especially if you can use your reconditioner to service the box from then on.

[jmw748]

Thanks Conan.

My thoughts exactly. My box now has full 12 months unlimited mileage warranty from The Automatic Gearbox Co in Rochdale after having new clutch plates etc throughout, new TC, Pump and a full in total pieces rebuild. I shall be having full changes done evry 40K from now on.


I agree a maual conv is starting to look a sensible option, even if it drops it to a simple RWD solution (mmm, 300bhp RWD sounds FUN!)

[jmw748]

Originally Posted by entwisi

I agree a maual conv is starting to look a sensible option, even if it drops it to a simple RWD solution (mmm, 300bhp RWD sounds FUN!)

Wouldn't my S8 stay 4WD? IIRC Audi sold A8/S8s with manual boxes in Europe, just didn't market that option in UK, didn't they?
Even the wife says that the S8 is worth ploughing some more money into - mind you, as long as it doesn't stem her flow of handbags and boots, she would say that!
Have to say that SIngh's comments and the dedication here leans me towards throwing just a few more quid the ol' girl's way (car, not wife )

[Architex_mA8tey]

glad to hear you're falling under the spell hehe (yes dear coming, ahem)

[Conan_the_Librarian]

For those thinking of it, for a manual conversion for a S8 you would need:

From a LHD Manual S8
6 Speed box
Rear Final Drive
Flywheel
Bell housing
Pedal set
Clutch master cylinder
Clutch
Propshaft

And you'll have to:

Recode the TCU
do a bit of wiring and plumbing............

Easy

Getting the parts is hard!

[Conan_the_Librarian]

and if u want on...
Here and Here

[Oli18]

Originally Posted by Ian@A8Parts

I'm sad to report that 7000 miles after this wonderful service, the gearbox in question started to develop faults much the same as any other box would at that age / mileage.

Whilst the ZF 'wonder-service' looked so, so impressive, our first impressions are now that perhaps its no more beneficial than a service by a good independent over here.

Perhaps, if serviced by ZF every 20-40K throughout its lifetime, then it may make a difference, but in reality many of these gearboxes dont get their first service until 100K plus miles, and it seems that damage is done by that point and the death of it is inevitable.

We are noticing (apart from the S8's) that the facelift gearboxes seem to last longer. We are thinking it may be due to the electronic throttle, which noticably backs off the engine during a gear change - Something that the pre facelift did not.... This is one of Davids theorys as hes very much pedal to the metal, and notices every split second that he's not on 'full throttle'... Since moving from a pre facelift to a post facelift, he's noticed this 'backing off' behaviour....

HI Ian,

Do you have a link of where the info was about the gearbox dying 7k miles later?

I was seriously thinking about going over there and doing that service as i'm off to holland soon and could swing by.

Would the changing of all the parts shown in that Bimmerboard write-up not help? The little ball and the piston they replaced were differently sized.

Gearbox pressure marble:



Main pressure piston:



I wonder if it's worth doing the service anyway

(a) to ensure the gearbox not only gets new fluid but the whole unit is thoroughly cleaned and

(b) the new parts should hopefully make the gearbox work better (why else change the parts unless it's an improvement on the old design?).

I'm not sure i get what actually goes wrong in the gearbox but what do you think...worth still doing at 76k or not?

Thanks,

oli