Help diagnose 99 eurovan transmission issue

[ryan1982]

I bought a 1999 Eurovan with 168000 miles in 2015. I bought it with transmission problems. The problems have persisted despite the following work:

169k miles: Installed transmission cooler and serviced transmission
171k miles: Replaced drive axle seal and neutral safety switch
175k miles: Replaced valve body solenoids and harness
175k miles: Re-adapted transmission computer and replaced valve body

The initial problem was that the trans would not shift normally out of first gear into second. It would go to 4000 rpms before shifting into second gear. My mechanic did a trans cooler and trans service, and the problem resolved. A few thousand miles later, the problem recurred, but this time it was mostly between second and third gears, and in warm weather. In cool weather, the trans shifts flawlessly; however, as soon as it warms up, the shifting between the second and third gears is erratic. Sometimes it will go to 4500 rpms before shifting. Other times, as the rpms are building, it will seemingly "slip" out of gear and lose torque for a split second before then going to 4500 rpm before shifting.

That said, city driving in warm weather renders the trans pretty much inoperable. However, my mechanic, who has done all the aforementioned work (supposedly guaranteed and $4000 later) not surprisingly tells me that he is having a hard time reproducing the problem.

Given that he's struggling to come up with any additional solutions short of continuing to drain my bank account, I'm looking beyond to anyone out here who might have some insight and wisdom to impart.

Thanks,
Ryan

[cc-91tech]

Hello Rayn,
What software does your mechanic use?
How is the transmission coding?
00000 is standard also dsp
00011 ecomodus
00012 sport mode
It sounds as if G68 sensor for driving speed - No signal,
Or the multi-function switch on the gearbox.
But first read with a VAG software and directly select the transmission control unit.
Greeting Andy
And write the error codes!

[ryan1982]

[gakali]

As you might already know, the kick-down switch activation is essential for proper adaptation. It's name is mis-leading as the switch is only activated at absolute foot to the floor wide-open throttle. It feels like a firm detent/sudden release feel on your foot when you push the pedal firmly to the floor. Unless you feel the resistance and than a sudden release of the pedal you have not activated the switch. Obviously normal transmission kick-down function usually occurs way before WOT. Actual kick-down does not use the "kick-down" switch (sounds confusing I know).

As far as I can tell the switch is really only used as an input during adaptation setting and possible clear-flood conditions. 100% throttle opening can occur without the switch being activated. The way that the switch works is weird as it's the pressure applied to the outer throttle cable tube after WOT that activates the switch. A mis-adjusted throttle cable will prevent activation of the switch and therefore adaptation is impossible.

All that said, unless you see the switch state change/feel the detent release with your foot while performing the adaptation the adaptation may not be successful. You can test the switch for continuity while a helper floors the pedal from INSIDE the van.

My 1999 tranny would delay up-shifting as you described when I got it. I did a service, put in a valve body and ribbon, (thought) I performed an adaptation, etc. and the problem persisted. Eventually I noticed on the scanner that while performing the adaptation the kick-down switch was not actually being activated while at WOT (a 0 bit should change to a 1 bit on the display). Long story short once I adjusted my throttle cable with the 11mm pedal spacer as per VW spec and performed the adaptation properly ALL my tranny issues were cured! This was over a year ago. As far as I can tell my tranny is an original at 244,000 km.

Of course I'm not saying that this is your problem, I'm just suggesting that you make sure that you're actually activating the switch during the adaptation. Don't assume WOT is actually kick-down switch activation like me


Hope this all makes sense and hope this helps...
_________________
Why do it? Because you can.

1999 Eurovan
2003 A4 Avant 1.8T Quattro
1992 W201 190e 2.3 Mercedes
2006 W220 S600 V12 Twin Turbo 5.5 Mercedes