Motor hunting (not the pursuing kind)

So amongst other little things with my TDI, I have notice something unusual. After it shifts into 2 gear (automatic) it will start to hunt from 30-55mph (48-88kph). You can hear it some but can also see the rpm needle just subtly move maybe only like 100-150 rpms up and down. Once I hit 60 mph it runs like a dream and has no problems at all. It will even hunt while in cruise control.

I've worked with a lot of semi's in the past and usually when a diesel motor starts hunting while idling (which mine does not), there is potential for the motor running away and that is never a good thing. It's done it for a few months now and my efforts to resolve it have not gotten me anywhere. It has some other symptoms too, but I'm going to try one more thing before I seek the forums help. I was just wondering if this is common and where I could start looking. Even if you could point me to another thread as my searching has not gotten me anywhere. Thanks!
-Uncle Spence

My 02 automatic also "hunted".
This is likely related to the transmission.
Get a VCDS scan to see if it has set any codes so you can knowledgeably diagnose it and proceed.

Yeah, it sounds like a torque conveter lock up clutch slippage issue. Very common for the 01M transmission.
If this is the problem then, you should be able to view this on VCDS as a difference in RPMs for input and output...I don't remember the measuring block number but someone else will.

This is likely related to the transmission.

Click to expand...

Yep, welcome to the 01M issues. My '01 Jetta has this exact symptom too. I have tried changing the fluid and even added a little of the Lucas oil to try and thicken it up. Didn't help much. More than drivable though. Been driving it like that over 6 months and it hasn't gotten any worse either. But in the meantime, I found a 5 speed manual transmission to prepare for its eventual demise. There is a lot of information out there about this. Try searching this forum or using Google. A 5 speed swap isn't the only option, the 01M can be repaired too.

Spenser

search "coolairVW". He posts a lot of info, diagnostics, and fixes for this type of issue. Welcome to the joys of the 01M. My best advice is not to let it slide, even if its drivable. a ~$400 valve body rebuild may save you $3-5K for a new tranny. The 01M can often be repaired early on when it has issues, but ignoring it leads to catastrophic hard part failures, which go up exponentially in cost.

sdeck said:

search "coolairVW". He posts a lot of info, diagnostics, and fixes for this type of issue...

Click to expand...

This ^^^

All sound advice everyone. Thanks for taking the time! Although the 5 speed (or even better 6 speed) swap would be nice, if I can salvage the 01M for a good while longer I know that would make the misses happy. I frequently find myself in the Kansas City area so I might just make my way to CoolAirVW personally rather than the trial and error method.

UncleSpence said:

All sound advice everyone. Thanks for taking the time! Although the 5 speed (or even better 6 speed) swap would be nice, if I can salvage the 01M for a good while longer I know that would make the misses happy. I frequently find myself in the Kansas City area so I might just make my way to CoolAirVW personally rather than the trial and error method.

Click to expand...

That is about the best plan you can make, IMHO. If I were closer, I would have done the same thing. Had to make do with shipping him my VB for a rebuild, but it went another 90K(ish). Still going.

Do it sooner rather than later. bad things happen to folks who limp around on the warning signs with this beastie.

I never did update this and find it helpful when problems are updated for other thread members closure and diagnosis of their own tdis.
I made the trip to Kansas City and CoolAirVW was gracious enough to open up his shop to me and even turned down a couple of people walking in from locally wanting him to look at their car just so that I could get back on the road.
He took me on a drive with VCDS and he explained what he saw and his theory. We took it back and he had a already rebuilt valve body that was installed. I was able to watch the whole process and gain from this experience. They even did a wheel bearing for me while the car was on the lift and it was pretty reasonably priced.
After everything was done we went for a drive again with the computer reading everything and he even let me drive it to see if I noticed there was a difference. The car drove beautifully and he even pointed out some other things that I should attend to before too long. I have since attended to those items and the car has run great for over 3000 miles. If you ever make it to KC be sure to look up Cool Air Auto for great TDI help.

thanks!