Sorry for another transmission thread

[cpinde]

To the vets I apologize in advance for yet another transmission problem thread.

I have an 05 Passat TDI with 135k miles on her. I bought the car a couple months ago to help me cut down on my fuel consumption, I drive 200 miles a day round trip. I got the dreaded torque converter code and a nasty torque converter shudder when I go more then part throttle. I put 2 quarts of fluid,
VW, in and half a bottle of Lucas Transmission fix and the problem went away completely for about a week. Never has the transmission slipped or hard shifted. I'm still getting 38mpg despite the TC not locking out.

I'm not seeing any leakage but it has to be leaking out, especially to lose 2+ quarts within 800 miles of highway driveway. Does it sound like the seal went bad? I need to get this car to last 3 more months, gotta wait to settle on my new house, and would rather do it without putting a bunch of money into it.

So without anyone taking a look at my car I'd love to have some guesses at what I can do to fix/limp it. Can I check the seal without splitting the trans from the engine? If I have to change the seal it's almost the same labor as doing a torque converter, right?

 

[cpinde]

I wanted to post a update with more findings.

I ran VCDS logs this morning going into work. The transmission/torque converter seem to be working perfectly. TC closes like it should, I have no codes, and the trans fluid temps stay in the 55-57 degree celsius range. But if I put more then 25% throttle I get a nasty shudder. So now I'm really baffled. Could it be the TCM corrosion issue? If so why would it have gotten better when I added fluid? Could it be that I have a seal leak and it hasn't taken out the TC yet? Guess I'll have to take the TCM out during lunch and see what it looks like.

 

[oilhammer]

What makes you think your shudder is a transmission problem? Sounds more like a clogged fuel filter to me (by your description). These fuel filters are supposed to be changed every other service... which means, at 135k miles, the one that is on there should have only been in place since 120k, and should be the SIXTH replacement since the car left the factory.

 

[A5INKY]

First this:

...I got the dreaded torque converter code and a nasty torque converter shudder when I go more then part throttle...Never has the transmission slipped or hard shifted...

Then this:

...I ran VCDS logs this morning going into work. The transmission/torque converter seem to be working perfectly. TC closes like it should, I have no codes...

Which is it? Once a TC blows, it is blown.

 

[peiphil]

What makes you think your shudder is a transmission problem? Sounds more like a clogged fuel filter to me (by your description). These fuel filters are supposed to be changed every other service... which means, at 135k miles, the one that is on there should have only been in place since 120k, and should be the SIXTH replacement since the car left the factory.

This exactly my thoughts as well!
The logic in my head sees the transmission being told to downshift and get out of lock from a signal from the gas pedal being shoved down but of course the engine starving for fuel makes everything shudder.
The transmission is likely just confused!

 

[Ski in NC]

Watch tach carefully when car acts up. TC unlocking/locking is associated with maybe 100-200rpm tach changes, depending on how much power the engine is making. If tach is moving proportionally with speedo, tc is locked and tranny is holding the particular gear.

 

[cpinde]

What makes you think your shudder is a transmission problem? Sounds more like a clogged fuel filter to me (by your description). These fuel filters are supposed to be changed every other service... which means, at 135k miles, the one that is on there should have only been in place since 120k, and should be the SIXTH replacement since the car left the factory.

Between the P0741and it taking 2+ quarts of fluid I figured the TC was causing the shudder. I changed the fuel filter at 128xxx and will try that again tonight just to make sure I didn't get a batch of bad gas somewhere.

Is there a block I could look at to make sure the injectors/fuel pressure are right? I'd love for it to be the fuel filter, I have extra ones so that's an easy fix.

 

[cpinde]

First this:
Then this:
Which is it? Once a TC blows, it is blown.

Both statements are true. I had the P0741 code and the shudder. But this morning I was logging as I came into work and the TC was locking. When I go home i'll log it and make it shudder to see if the log shows the TC locking and unlocking or slipping.

Any ideas on what else I could look at to see?

 

[cpinde]

This exactly my thoughts as well!
The logic in my head sees the transmission being told to downshift and get out of lock from a signal from the gas pedal being shoved down but of course the engine starving for fuel makes everything shudder.
The transmission is likely just confused!

It shudders even when I don't push the pedal hard enough to cause the trans to downshift. Like gently "rolling" on the throttle on a flat surface.

Its driving me crazy that I can't figure it out. Haha

 

[peiphil]

It shudders even when I don't push the pedal hard enough to cause the trans to downshift. Like gently "rolling" on the throttle on a flat surface.

Its driving me crazy that I can't figure it out. Haha

When you change the fuel filter tonight you might check that the fuel lift pump is working correctly as well

 

[A5INKY]

Both statements are true. I had the P0741 code and the shudder. But this morning I was logging as I came into work and the TC was locking. When I go home i'll log it and make it shudder to see if the log shows the TC locking and unlocking or slipping.
Any ideas on what else I could look at to see?

Unlike so many other cars and trucks with failing TCs, The few B5.5s I have seen fail did not shudder, TC just defaulted open.

I would monitor MB 23, individual injectors switching times. I have seen an individual injector cause a shudder under accel that didn't initially set a DTC, let alone a CEL. Watch these values as the shudder happens. It will be obvious if an injector is laying down.

When you change the fuel filter tonight you might check that the fuel lift pump is working correctly as well

Lift pump alone will not cause what OP describes. Not worth looking at yet.

 

[sschnath]

Had a shudder that acted very much like a clogged fuel filter several years ago. Turned out to be a dirty EGR valve and it took a while to figure it out.

 

[whizznbyu]

What makes you think your shudder is a transmission problem? Sounds more like a clogged fuel filter to me (by your description). These fuel filters are supposed to be changed every other service... which means, at 135k miles, the one that is on there should have only been in place since 120k, and should be the SIXTH replacement since the car left the factory.

Brian, do you use the factory filter or are you OK with Hengst, Bosch, Mahle, or Mann?

 

[oilhammer]

The few times I have had need to replace a filter, I just get one from the dealer. I thought Filtran is who makes them, but I may be thinking of the 01M (they may BOTH be Filtran, though).

 

[cpinde]

What makes you think your shudder is a transmission problem? Sounds more like a clogged fuel filter to me (by your description). These fuel filters are supposed to be changed every other service... which means, at 135k miles, the one that is on there should have only been in place since 120k, and should be the SIXTH replacement since the car left the factory.

ALL HAIL OILHAMMER!!!
I changed the fuel filter tonight and went for a short drive with no shudder. I'll run it 200 miles tomorrow going to work and get the final verdict. I couldn't see past the newish fuel filter and torque converter code. I had a Honda Accord that when the TC went bad it shuddered just like my Passat was doing. I've got my fingers crossed that the fuel filter fixed the problem.
I went through my receipts and gas station fill ups. Found a combo that I think clogged the 6000 mile fuel filter, a diesel Kleen treatment and a suspect gas station fill-up.

This exactly my thoughts as well!
The logic in my head sees the transmission being told to downshift and get out of lock from a signal from the gas pedal being shoved down but of course the engine starving for fuel makes everything shudder.
The transmission is likely just confused!

I babied the gas once it shuddered on me so the fuel rate didn't get to the "clog" point. I bet your right that the fuel starvation pissed off the transmission.
Thanks for helping me see the trees in the forest.