I need help. I have a 2003 1.8T jetta with a 5speed automatic transmission (GNZ code).
Problem started with no 3rd speed available when cold, after running a few miles and tranny gets warm, 3rd speed will become available but in the meantime, tranny will shift rough from 2nd to 4th with rpms high (of course so it can reach the speed for 4th to be available). When the transmission is cold and if I try manual shifting, the transmission tries to engage 3rd speed but it can't then it goes back to second.
Now 1 more problem added to this, now whenever it's time for the 4th speed to kick in, it doesn't engage. It disengages 2nd(when cold) or 3rd(when warm) and it can't engage the 4th speed, rpms go up (of course due to not engaging the speed) and I have to wait for the rpms go down to idle speed and accelerate again so the 4th speed can kick in.
Recently, whenever I'm changing speeds manually, If i decrease from 5th to 4th or 4th to 3rd(when available) instead of rpms going up (like it should due to lowering the gear at higher vehicle speed) they go to idle speed.
I haven't check for codes yet, I will do that tonight and post whatever I find tomorrow. In the meantiem if anyone can help me solve this I will be forever thankful since I don't want to spend $5000 on a new tranny ( I hate VW does this, not selling internal transmission parts )