Auto trans issue

Sunday I was driving thought the mountains of West Virginia. After about 45 min of spirited driving up and down several twisty mountains I found that my torque converter would no longer lock-up. Everything else about the Trans seemed fine. I managed to get to the ski slope fine, just with an unlocked torque converter. After a day of skiing everything seems to work fine. Has anyone ever experienced this before? I head home on Wednesday afternoon and will see if it happens again although I think I may take it a little easier through the mountains since it is a 6 hr drive home.
Thanks in advance for any advice.

When I was towing a 1200lb trailer through algonquin park that happened to me since there was so much shifting (sitting in the 70-90km/h speed limit it was just off power all the time) if IO was wise I would haveleft it in 3rd gear and been fine. Never did it again even up through the hills along lake superior on the way to winnipeg. i think the tranny was getting a wee bit toasty

If I leave the winter rad cover on my car I can get the tranny to do it on a +10C day.

Not sure actually, but it may have been smart enough to know that you were driving in mountains (a matter of requested torque vs speed) and unlocked the convertor for a while. That and it may have gotten too warm which resulted in the same thing.

Mine never "reset" itself back to normal mode if it had indeed unlocked the torque converter with fuzzylogic, I had to stop the car after the national park and take an extended pee brake to let it cool down, then it was back to normal.

If it were me I would think about changing your fluid after this happens. I have similar mods on an auto that I drive hard and the fluid VW put in it had quite an interesting smell after just 35k miles. Plus it gives you the chance to clean all those metal shavings off the magnet.

Mines never had any metal "shavings" on the magnet, I changed the fluid after the trailer towing this past summer. Mine only has ever had a light black collections (like fine iron filings, very very fine). The amount was very small, like a black smudge on the magnet. The oem VW fluid smells bad when it is new FWIW.

What I would like to know is which is the coolant inlet to the tranny so I can splice additional precooling of the coolant in to that...

Same code that mine threw. It was ok for a while of easy driving, but had to rebuild the tranny within 3 months.
A local shop did the rebuild, puting in a new T/C, and new valves, my clutch packs were all ok to reuse. I suspect they used an aftermarket T/C, it never has felt quite the same since, so you may want to make sure OEM is used.
I know it's not what you want to hear, but you may be in the same situation a whole load of us have been in over the past 6 months or so: The Curse Of The $5K AutoTrans.
Rebuilding cost me about 1/2 of that FWIW.

I would check your fluid level asap 4vdub. It is very sensitive to proper level and you already have vag-com to do it correctly. I would do it asap and then change the fluid and filter.

I just swapped mine when it had problems...

mine would do that sometimes when i had an AT 2002 jetta. I would do the push the go pedal in all the way to the floor, turn the key to on and hold it for 15 secs, then strart to clear the ecu. That always worked to reset it. I always thought it was overboosting or someting and going into some kind of limp mode. I had a vnt 17, pp520s, and RC2, RC3, RC4. It did it with all the RC's. FWIW as an aside, I liked RC3 better than RC4.

It would be sweet if you could make a manual lockup switch.

Also the new beetle (MKIV) came with the dsg and tdi. So that might be a good alternative to another AT. There is always vw4motion (petr) who can get 6spds from Europe too. His parts take about 10-14 days to arrive and I have had nothing but good experiences with him.

I wonder if you're getting an intermittent power signal? I had an intermittent fault in mine, but it was a ground issue.

TC slippage was one of my symptoms before major metal found in fluid at 100K. My rebuild with 24K warranty was $3K.