2003 jetta tdi auto transmission problem

Hi there. I own a 2003 vw jetta tdi with the dreaded auto transmission. I purchased the car this past april. It has 407km on it and was told the trans was flushed prior to purchasing it. It drove fine up until september. I can drive it and shifts through the gears normally but after a couple hours of highway driving and then city traffic it all of a sudden wouldnt shift past 1st gear. This happened to me twice in 2 weeks and after getting out of city traffic and back on the highway it was able to shift again. Driving it an hour the other day it was driving fine and then went it shifted down going up a hill it would no longer shift back up to overdrive. After sitting the night all works again. Any ideas what could be causing this in the transmission?

Sounds to me like a solenoid(s) issue. Pull the transmission codes for direction


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Thanks. Will look into it

A buddy bought a Jetta wagon 2.0 gasser wagon for his daughter. It did somewhat similar. Scanned the TCM and the code related to a sensor on the exterior of the tranny (Gxx-I forget the exact designation). $25 and all has been well for quite some time now, but the 01M automatic isn't ever going to be bulletproof.

jettawreck said:

A buddy bought a Jetta wagon 2.0 gasser wagon for his daughter. It did somewhat similar. Scanned the TCM and the code related to a sensor on the exterior of the tranny (Gxx-I forget the exact designation). $25 and all has been well for quite some time now, but the 01M automatic isn't ever going to be bulletproof.

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Probably the G68 sensor.

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Sounds like a temperature issue - either the sensor, or it is actually running hot. The factory "cooling" system on the 01M actually keeps the fluid too HOT, and especially in city driving can cause the temperatures to rise above 230 degrees.

I'm not sure if the G68 sensor is the temperature sensor, but I'd start there (sensors are usually cheap and don't last forever) and then look at upgrading the cooling to an external cooler.

Transmissions also need new fluid and filters about every 40k miles, where VW and their idiotic "lifetime" nonsense with this transmission can DIRECTLY be blamed for most of the poor reputation it has. This transmission will run great with Mercon5 fluid in it, per the advice from Import Performance Transmissions who builds the 01M into an actual quality unit. I've got one of his builds, and it is amazing.

Thats great advice. I will start with the sensor and go from there. I agree that it seems like it gets too hot so i will also look into an external cooling method. Any cheaper ideas?

Cheaper how? An external cooler isn't that expensive, the adapters are about the same cost as the cooler. You can get just about any Hayden cooler you want at your local auto parts store. I went with a 12" by 15" by 3/4" cooler that (IIRC) had 5 loops of tubing through it, and mounted that on the front of the existing stack.

Get quality transmission hose from your local auto parts store and you want the high pressure stuff. Here's the adapters you need:

https://www.amazon.com/Sonnax-11981401K-Remote-Transmission-Cooler/dp/B072FRVNGR

The AC fans are on whenever the AC is running (mine pretty much always is) so there's no issue with airflow. With an external cooler, the transmission fluid will be about 175 degrees normally instead of over 200.