What's causing gearbox to "hunt"?

[Dieseldan73]

Hi All.
New here and this is my first post:
I have a 2003 A8 4.2
My problem is that the gearbox often seems to be hunting to find the right gear. Constantly changing up and down.
Most noticable at low revs and 30 - 40 mph.
I couldn't find a specific thread to answer this, but seem to remember someone suggesting a gearbox oil change to solve it.....
Is this likely to be a suitable fix? Any idea of cost ('cos if cost weren't an issue I'd be driving a 2009 4.2 TDi instead )

Any help will be appreciated........
Thank you

[Crasher]

You need to have an engine and box code read done but I have seen numerous A8 V8’s with box problems the only cure for which has been an exchange Audi box at around £2900 plus fitting.

[sanjx]

having done quite abit of research in the last month, the problematic boxes seem to be D2's. THe D3 is quite a robust box. Hunting can be caused by many things, from my limited experience of 2 auto's (both which failed on me) i would be tempted to say that you should try getting codes read for the sensors. speed sensors and cornering sensors can cause issues. also check all your tyres are inflated correctly and wearing evenly, as un-equal pressure can cause the gearbox to think your cornering and play havoc with the box.

let us know how you get on.

[shadow8]

My D2 gearbox was replaced with a new one 2 years ago. Speak to any of the D2 owners and they'll tell you that the gearboxes are a weak point on the A8/S8. Changing the oil does help as it gets dirty very quickly and this should be an annual task using an independent engineer like 4 Rings who know what they are doing. Audi ********hips will tell ,you the gearbox is a lifetime sealed unit but it's not and the oil really does need changing, At my last change my box was starting to hunt and an internal oil seal had perished and was replaced and everything now hunky dory but you do have to keep your eye on the G/Box because it isn't as tough as they tell you.
Good luck
Tony

[a8 tech]

The interval set by ZF and Audi is lifetime fill so the dealers are correct as per service regime,i also believe the oil should be changed and the pan filter but the internal seal between the diff and the valve chest is the culprit and the two differing oils mix causing all kinds of issues but then again we use a different oil from 2004 onwards with some sw updates for gear change issues and the failure rate is very very low considering this platform box is used across the Audi platforms and most early A8 suffered from poor airmass meters which caused premature failure of the clutch packs hence burnt discoloured oil.

[Dieseldan73]

Thanks for the replies so far. I like the idea of checking the tyre pressures as I can do this myself!!!
It is a D3 model that I have and I think my next step will be to get the oil changed to see if it helps or even fixes the problem. Will keep you all posted.
Unfortnately the most local dealer to me has just emptied his showroom and forecourt of cars, I am guessing they have gone belly up and haven't just had a record sales weekend and sold everyting.

Can anyone tell me what a sensible price for agearbox oil change should be, so that I don't end up paying over the odds.
Thanks again.

Danny