2001 S8

I've been reading several threads about A8/S8 transmissions and transmission issues. In fact so much reading, I think I'm become neurotic : )

My 2001 S8 has 92,500 miles on it. The transmission seems to be working fine (knock on wood). I don't have any history of whether the transmission has ever been serviced, prior to me owning it. I bought it 4 months ago with 89,750 miles.

I'm thinking about doing a complete transmission service (fluids, filter, seal, etc.) But I've seen several comments that if the transmission is operating fine, just leave it alone.

I'd like to get feedback from fellow D2 owners on this topic.

Thanks.


2001 S8
Black on Black

silverd2

THAT, sir, is the $5000 question?

You might as well ask if anyone "knows" for sure whether there is an afterlife or not.

I have personally never seen anything that I consider evidence positive that it makes any difference in the long run. Scientific theory says one thing and actual anecdotal statistics don't seem to support it. I've seen identical cars, driven the same way have transmissions die at 185K miles...one serviced every 30K miles and the other never touched. Never have a seen a pattern of regularly serviced ones not dying at the same mileage range compared to those never touched.

I have also never seen (barring being significantly low on atf) changing the fluid/filter actually "curing" a significant problem...minor "symptoms" lessened maybe(?)

99% of the reason I changed mine (atf & filter) at 100K miles was because I just wanted to see in there...same reason I took apart my toys right after Christmas when I was little
I used as an excuse a couple of minor things I noticed: A slightly rougher downshift (not a "slam") to 1st gear coming to a stop, maybe 1 out of 10 times...and a barely audible trans pump "whistle" sound (esp when cold) for the previous 50K miles.

The whistle and the occasional rougher shift to 1st lessened just a little for maybe 5-6K miles, but now 27K miles later are pretty much the same , but trans still works great in all respects.

I do firmly believe that changing the filter can not be a bad thing in itself (win-win in fact), although there is some wisdom in having fear of introducing new atf to an old trans, with all the fresh detergents in it...the theory is breaking loose "useful debris" that was serving as friction material to fill in on worn clutches. I have heard several horror stories about very old trans's failing shortly after new atf, esp if the old atf was really dirty and burnt.

Some have even changed filters and returned old atf into the trans, with long term good results and peace of mind...there is wisdom there. I had considered this myself, but after seeing what good shape the old atf was in, I felt good about putting new atf in.

In the long run I was glad I changed mine because of what I discovered...no sludge, magnets only had a thin coat of fine powder (no shavings), the atf still had color and no burnt smell. Mine may last no longer than any others, but the look inside gave some peace of mind.

omarcarbomb

first let me thank all that commented on the proper amount of ATF fluid need for the job. I had my mechanic pickup a few more liters than the 6 I had on hand (shame on blauparts for only selling kit with 5 L).

I kept my old A8 as parts car for the sole purpose of parting out its newly rebuilt transmission when the one in my current daily driver failed (knowing this was an inevitability).

Almost perfectly on schedule the transmission went into limp mode at 162K miles. There were warning signs over the past 6 months as the regularity and magnitude of the clunking was slowly increasing, thought the car was driving just fine.

I had the filter fluid kit sitting in my garage waiting for the swap to take place since doing the fluid filter service while replacing the transmission would be less labor.

the rebuilt donor transmission had only 25k miles on it and didn't need the servicing but since I was getting it done for very little in the swap I did it anyway.

my mechanic reported that the fluid was nearly new at 25K.

At least now I have a very low miles transmission with new fluid and filter. Should get 85K miles out of it (which will put the engine at 250K miles)

I suspect that the transmission I replaced may have been good and that the problem could have been the torque converter.
But why do labor on torque converter to still have 160K+ tranny?
May as well put in new one.

There have been many posters who claim to be tolerating less than factory transmission performance. From clunky shifting to having to pull over and reset regularly after limp mode.

Having my transmission being new again has reminded me of how amazing these cars really are and I assert my earlier claim that if you are driving (an A8) on a marginal transmission you may as well drive a Honda with a good transmission.

If you can't afford to maintain/replace these zf5hp24's you should not be messing with these older A8's

It is wishful thinking that you will be different than everyone else. Your transmission WILL fail and the car is not the same without a smooth transmission. I also agree with silver that it is wishful thinking that fluid/filter change will fix limp mode.
this is urban lore spread by guys selling limpy A8's on CL trying to convince suckers that all the car needs is a fluid change. Would you buy a clunky 160K miles engine on the premise that all it needs is an oil change? no.

I have been loving driving my car again and the transmission was working OK before it went into limp mode two weeks ago

If you put the money into a new transmission you will not be disappointed and will only be reminded of why you love your D2 so much.

since someone will ask...

I paid $1800 to have the donor removed the limp one removed and the donor re-installed. That included the filter and fluid change.

A small (or medium) price to pay for such a fine ride

Adjuster

In the three A8's I've owned, the transmissions have been an interesting deal.

The 1998 had a failing one when I bought it, and put over 78K on that failing trans.. Just had to shift in Tip mode, and it was fine...

The 2004, with only 13,700 miles on it when I bought it had some weird clunks and shifts every now and then, even so new... but it worked fine the rest of the time.

The 2001 S8 I have now had about 75k on it when I bought it.
The car is a prior total loss.
The oil pan on both the engine and trans are newer than the engine and transmission, and there are signs of the underside being scraped over a curb, or something concrete, most likely taking out the pans that were then later replaced.

The fluid in the trans was nearly new. Very clean. No debris, no metal flakes etc. It worked fine, and I had no idea what maint. schedule the prior owner had done, and he had no idea it was a prior total loss, so I can only guess the fluid was new when the pan was replaced when the car was wrecked.

So, why did I change out the fluid? Well, I wanted to run synthetic fluid, and I wanted to do it cheap.

So, I used AAMCO, and their "House" synthetic trans fluid they buy in bulk, and use on the lifetime rebuilds they do. (So I know the fluid is good, it has to be, or they would be replacing transmissions under warrenty, and that costs them money.)

Cost was just over 200.00 for the whole deal. And they changed out my front, center and rear diff fluids with their house synthetic gear oil too.

Great peace of mind.

Will my trans fail at 170k or there about? I have no idea, but I doubt it will be due to fluid failure.

Am I going to change my timing belt at 90k? Nope, I'm going to inspect it, and if there are no cracks, signs of wear, or leaking water pump, keep going till 130k, then change it, and the trans fluid again just as a precaution. (About 50,000 miles on the fluid at that point.)

omarcarbomb

one week later it is running perfect.
have to get used to the car downshifting more often.

seems like the failing tranny/torque converter had not been as aggressively downshifting almost like it was floating up at higher gear and lower rpm.

notice this when pulling into neighborhood in 4th going 35mph
failing tranny would stay up in gear longer till the rpms dropped off and then catch up with a little clunk (barely noticeable)

the new transmission shifts more as it is in the correct rpm range constantly.

that is the design right?

silverd2

Some of that has to do with the soft coding. How do have that set?

ScotD

Change it. The best example I can find is this. This is my fluid after 65K miles.

2001 S8

Looks like there's a sad face in your trany fluid. LOL

Adjuster

More like a curious polar bear in that oil...

I've been really happy with the 200.00 price for having the work done at Aamco, and I don't get dirty, and it's about what you'd pay to buy just the Audi fluid/filter/gasket.

And they changed out my front, rear and center differential fluid/oil as well, using their house multi-weight synthetic of course that they buy in bulk. (Think the guy says it was 75-90? and had the additives for limited slip, and I've noticed my diff's do make some noise when I'm turning tight at low speeds, such as going around and around up parking garage ramps where when you exit, you might go down 4 floors, all turning left in a tight turn for the whole time.)

It sounds like a shudder, and I've noticed it on every limited slip diff vehicle I've owned that was working properly. (I had one Supra, where we added some moly to the oil, and it made the clutch pack sticky, and the diff would not "unlock" very easy, so it would actually chirp the tires at slow speed, tight turns in parking lots.. as well as make some pretty loud noise and pops as the metal friction and steels in the diff pack finally slipped, or the tire chirped depending on the temp and surface. (On ice, it was actually dangerous, the vehicle would lock up the rear, so both tires would break free and slide.)

But in a launch, the tight diff, was Awesome for laying down a good burnout, not like a spooled diff, but pretty dang good for drag racing. We ended up washing out the moly, and it was better, but still very tight, and I found that just a few ounces of that moly oil would tighten up any clutch pack type diff for drag racing, or if you wanted to "drift" as they call it today, and slide the rear around by equally spinning both rear wheels under power.

Prospeeder

ZF the manufacture of the trans say 40-60k service intervals for the fluid. Audi, who wants a new car buyer to think the car is maintence free and cheap, they want you to buy a new car, and could give a **** if anything last longer than the warrenty. So who are you going to listen to, the people who made the trans and want it to last, or the people who want you to buy a new car.....Just change the fluid and the trans will return a nice long service life. Anyone who thinks any lubricant lasts forever is sadly mistaken.

And anyones fear of changing the fluid and hurting it is complete bs and is a total myth. I have serviced so many audi transmissions with 100k+ on the same fluid, black gross, and yet to EVER have one have a problem afterwords. These idiots who wait till the trans is acting up like hell, change the fluid in hopes to help, it dies in a month, seem to think it must be because of the fluid, not because it was dying anyway cause they didnt service it....