[A4] A4 Tiptronic slipping

[Scott Simmons]

The "all gears light up" means the transmission has detected a fault and 
gone into "limp" mode.  Yes, only one gear and reverse works.  Usually 
it's 4th gear but it seems like I read something in the Bentley saying 
it was 2nd, which is odd.  I'd recommend scanning the TCU for codes.  It 
could point you in the right direction of a faulty solenoid or whatnot.  
Sounds like there's either air getting into the fluid (fluid low, crack 
in the pick-up tube, etc.) and not building enough pressure, or one of 
the magical, mystery components is going south.

I work in the automotive aftermarket.  I've seen all sorts of "turf 
wars."  People who swear by something 110%.  "I would never use 
Pennzoil!  That stuff ruins engines!"  "Always let the car idle for five 
minutes if it's cold outside!"  Stuff like that, y'know?  Most of the 
time I know that it's just bupkiss and old wives' tales.

There's one out there about the ZF transmissions.  I know it's in the 
Audi world but it could be in the VW and BMW and MB areas too, I just 
don't know so I can't say.  This idea that you should never, ever change 
the fluid in your ZF transmission if it's never had regular (40k) changes.

At first I was like, "Uh, whatever."  When else would you recommend 
something like that?  Engine oil?  Would you never, ever change your 
engine oil just because you (in our fantasy) went 80,000 miles?  Hell 
no.  It's good, preventive maintenance to change that crap, regardless 
of how old it is.

Or so I thought.  There's this guy, Tozo.  He rebuilds ZF transmission, 
basically for a living.  And this guy says that if it's not been 
changed, and the transmission is acting fine, don't touch it.  He says 
that he's seen it all too often, that someone will change the fluid 
after 100,000 and not even 10k later, the transmission goes out.  The 
new fluid breaks loose deposits on the clutches and moves those around 
to gum other things up, etc. etc.

Really??

So I talked to a local transmission shop and they said to just change 
it.  That most of the time this stuff happens because someone has a 
little bit of transmission trouble or maybe none at all, changes the 
fluid, and then the transmission shells out 10,000 miles down the road.  
Well, the problem would've probably happened anyway.  While "cause and 
effect" are sound methods of science, "Post hoc ergo propter hoc" is a 
common logical fallacy.

I also popped into a VW Passat forum.  They use the same ZF5HP19 
transmission, just the FWD version.  Most of the guys on there said to 
just change it and were a bit upset with me for asking, seeing how it 
was something "covered a million times before."  Hm.  I was asking, 
though, specifically about folks with transmissions >150,000 changing 
for the first time.  *shrug*  The only thing they said that was 
semi-agreement was to NOT flush the system, but to do progressive 
changes.  They claimed that a flush would damage the clutch facings  My 
transmission shop said, "Eh, maybe." to that idea. 

Most of the research I've done says "change it."  But this ZF expert 
Tozo and even BMW and Audi factory literature say "don't."  Stuff 
between Iraq and a hard place.

Does this apply to you?  Yes and no.  You're already having transmission 
issues.  I would pull the codes and see what they say.  I'd also change 
the fluid and filter.  At this point, it couldn't hurt.  The fluid, 
based on other people's experiences, will probably be completely black. 

Don't go to AMACO, FFS.

Find a local, reputable transmission specialty shop.  I went with 
Certified Transmission because I've sold their product before on the 
retail end and the guy not only cut me a deal on a transmission for the 
wifey's car, but their work was top notch.  What really sold me on them 
was the guy was willing to give away information for free.  Everyone 
comes to me for free info on how to fix their car in my line of work and 
I know it's trying.  It seems like most of the non-retail automotive 
groups don't want to help with that and I can see why.  But this guy 
gave me suggestions on how to try to fix the wife's car, how to do some 
diagnosis at home, before we decided that it was just toast. 

I know this is an aside, but it's a good story related to the above.  My 
history with the wife's car, a 1996 Chevy Lumina, is only 5 years old, 
about.  We really have no service information before I met the car (and 
the woman that came with it).  So I had to assume nothing had been 
done.  We did the basic forget-me-maintenance: fuel filter, transmission 
filter, etc.  We changed the transmission filter every 2 years, even did 
a full flush.  She's not aggressive on the transmission, it's never 
given us issues, the fluid was always red and clean-ish.  And then, 
slowly over the past summer, it developed a slip when cold that got 
progressively worse.  We changed the fluid every 20-25k miles and the 
transmission still went south.  Would it have gone bad if we never 
touched the thing?  Probably, sooner!

But that has nothing to do with you, Kent. ;)

I know it's unfair to the smaller, less affluent shops, but I will 
generally look for the biggest, most friendly ad in the yellow pages 
when I'm finding a new mechanic.  I then ask around to see if anyone has 
had work done by them, or if they have any other suggestions.  Talk to 
the commercial side of your FLAPS.  Try to get them to be honest, which 
may be easy or hard. 

This could just be low or dirty fluid.  Or you might need a new 
transmission.  It's the one thing I dread about these cars.  Engines can 
be rebuilt "fairly easy."  Transmissions are this magical, voodoo box.  ;)

FWIW, at the end of this long email, I did a lot of research into this 
because I'm a big preventive maintenance person who "can't" afford a new 
transmission for the car.  Some things, like the chassis, I don't jump 
on immediately because I "can" afford to replace those if they break.   
Also, I'm replacing the radiator here very shortly and plan on losing 
some transmission fluid.  Adding the fluid is half the work of changing 
the filter, so why not do both at the same time?  Well, Mr. Tozo said to 
not lose fluid, go to such extremes as using compressed air to blow the 
old fluid out of the old radiator's cooler and back into the 
transmission.  Really??  Who am I supposed to trust? :)

Good luck,
Scott S.

Kent McLean wrote:
> 1999 A4 V6 with Tiptronic -- the transmission is starting to act all funky.
>
> Sometimes it acts normal.
>
> Sometimes, when taking off from a stop, the engine will rev like you're slipping 
> a manual transmission clutch, and the car will take off, but more slowly, as 
> though the clutch is slipping.
>
> Sometimes, when coming to a stop, it will go Ka-Lunk! real badly, like being hit 
> from behind at 2-3 MPH.
>
> Sometimes, when taking off from a stop, it will rev like it is in neutral, then 
> Ka-Lunk, it will bang into 1st.
>
> Sometimes the PRN54321 indicator on the dash, which normally lights up whatever 
> gear it is in, will light up all the letters/numbers. When that happens, it 
> seems like its in 3rd gear; from a start it feels like you're slipping the 
> clutch on a manual in car, taking off from 3rd.  Moving the shift lever to +/- 
> manual mode does not switch it into manual mode; all the lights stay lit. 
> Turning off the car and restarting it resets the lights to act normal.
>
> With the A4 Tiptronic, there is no dipstick to check for fluid. It all happens 
> with a drain/fill plug on the transmission pan.
>
> Suggestions? I'm thinking of taking it to Aamco for a transmission fluid flush. 
> (Torching the car is nice thought, but is not an option.)
>
>