Auto Tranny Torque Converter Lockup NOT Locking Up

Biodezl

Veteran Member
Joined
Aug 8, 2002
Location
Davis, CA
TDI
Passat, 2005, Teal; Golf, 1999, Metalic Green, Auto
I'm not sure if this is the right place post this...but since I thought my problem might be due to insufficient transmission fluid...perhaps I can get an answer or two.

About 50 miles into a 75 mile trip this morning I noticed the engine running faster than usual for the given (undisclosed) speed. Playing with the go pedal a bit it behaved as though the torque lock-up was not locking up. I'd give it more "go" and when the RPM increase would usually track the MPH increase, it now seemed as if it were "free wheeling."

So, my suspicion is that I've lost some of my tranny fluid, or did not put enough in there. I did a change out a while ago and then noticed some spillage after 2000 miles or so. I attempted to re-seat the tranny cover last weekend, but perhaps I was not successful?

So my question: Can low transmission fluid cause the torque convert lock-up mechanism to fail?

Before you get too confident about your answer, I briefly turned the car off at a stoplight and the problem went away!

If this is implausible, then my next guess is that I might have a steam bubble in my coolant lines...that may have overheated the tranny. Is it possible for the tranny to go into "limp mode" without triggering a CEL?

All hail the mighty TDI gods!
 

TDICa

Veteran Member
Joined
Jun 26, 2003
Location
Sacramento, Ca
TDI
02 Jetta GLS Black
Re: Auto Tranny Torque Converter Lockup NOT Lockin

Did you change the filter when you changed the ATF?
Yes, low ATF or plugged filter can cause no lock-up, but you should also notice delayed shifting from 1-2 and 2-3. Another cause could be a sticky or worn out stroke valve that controls the TC lock-up. This is usually a problem with trannys >150K miles. You may also have communications problem between the tranny control module and the ECU. Lastly, there's a laminated wiring harness in the pan. If there's any fluid invasion into that harness, you'll begin to loose control of your shifting solenoids. Bottom line hook it up to a vagcom and see if you got any error codes and verify proper fill level.
Good Luck..
 

Biodezl

Veteran Member
Joined
Aug 8, 2002
Location
Davis, CA
TDI
Passat, 2005, Teal; Golf, 1999, Metalic Green, Auto
Re: Auto Tranny Torque Converter Lockup NOT Lockin

Ok. Since the problem seems to be intermittent, I'll work on these pointers this weekend. Dlai offline mentioned that Kerma experienced problems with a solenoid failure. Anyone know what is the part number? Link to that thread?
 

dlai

Top Post Dawg
Joined
Jun 6, 2002
Location
The Insane Asylum Known As CA
TDI
2005 Passat, Stonehenge Gray, 2002 Black Golf 5M
Re: Auto Tranny Torque Converter Lockup NOT Lockin

Biodezl: I was trying to find that old thread but am having no luck so far. It was someone who had the problem and Kerma helped him debug it. I think it was about a year ago or so...
 

l1o9s7t6

Veteran Member
Joined
Apr 11, 2005
Location
Alaska
TDI
jetta, sedan 2002 blue
Re: Auto Tranny Torque Converter Lockup NOT Lockin

I have a converter lock up problem also. Vag-com says mechical failer. Becareful and try not to drive a long time with it not locked up. My did it just did it two days ago and I hook up vag-com while I was driving my fulid temp was 260 F and climing, I stopped play around and got it to start working, after that it only took about 2 miles for the temp to drop down to around 120 F.
 

Biodezl

Veteran Member
Joined
Aug 8, 2002
Location
Davis, CA
TDI
Passat, 2005, Teal; Golf, 1999, Metalic Green, Auto
Re: Auto Tranny Torque Converter Lockup NOT Lockin

There was a code stored on my ECU:

P0740 "Torque Converter Clutch Circ Malfunction"

So is this the solenoid failing, or low fluid level? Something else?

And regarding the Transmission Specialty products... where do you purchase this device? I did not see a way to order this part from their web site.

Thanks,
 

TDICa

Veteran Member
Joined
Jun 26, 2003
Location
Sacramento, Ca
TDI
02 Jetta GLS Black
Re: Auto Tranny Torque Converter Lockup NOT Lockin

The error code is just telling you what you already know; so the dealers service department can verify your problem. The root cause of the problem can be anything. I'd start with ground points under the wiper blades, next to the ECU & TCU. Hit the connectors w/contact cleaner.
Any transmission rebuilder or parts house can special order you those parts. If your going to do this - order a valve body rebuild kit and make sure the laminated ribbon cable comes with it. A quality rebuild kit will usually include new solenoids and bushings to rebuild the TC stroke valve.
Good Luck..
 

Biodezl

Veteran Member
Joined
Aug 8, 2002
Location
Davis, CA
TDI
Passat, 2005, Teal; Golf, 1999, Metalic Green, Auto
Re: Auto Tranny Torque Converter Lockup NOT Lockin

Yes. I changed the filter the last time I replaced the tranny fluid. I'll double-check the fluid level using the appropriate VAG-COM procedure, again.

Does anyone know a good mechanic in the Sacramento area? I'm done witht the stealers.
 

enatman

Well-known member
Joined
Apr 3, 2004
Location
PA
TDI
current 2006 brm, 2014 passat SE returned, 2000 jetta 404k (sold)
I'm having a simular problem. I was driving and the car (2000 jetta automatic 245k) at 65, it suddenly downshifted from fourth. Then starting out, it didn't start in 1st, only second? I turned off the car. It worked fine? (reset itself?) now it's permanent? We looked at the tranny..it was fine? we replaced the solenoids, same problem, then the valve body..same problem and error code? We bypassed this with a shaffer shifter and it worked fine? Could it be a TCU? I was told ECU.. but after reading? bad connections? wiring harness?? Help
 

Biodezl

Veteran Member
Joined
Aug 8, 2002
Location
Davis, CA
TDI
Passat, 2005, Teal; Golf, 1999, Metalic Green, Auto
Re: Auto Tranny Torque Converter Lockup NOT Lockin

Ok. I checked the tranny fluid level this past weekend and it was a little bit low...perhaps 1/4 liter. When I filled it up, the lockup problem is solved and now it drives much more predictably. Thanks for your help, all!
 
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