04 Passat weird trans issue

I have an 04 TDI Passat. VW replaced the trans and TC around 80k miles ago. The trans hasn't given any issues.

This morning I put the car into reverse, and it sorta clunked. First time it's ever done that. Once I put it into drive, it wouldn't move at all. RPM would raise, but nothing. Almost like the e brake was on. Zero fault codes.

Turned the car off and on, and everything has been completely fine?

Any ideas?

Weird one.

I suspect your car is an '04 - there weren't any 2003 TDI Passats, only 04 and 05.

The only way to be sure would be to (if no codes set) scan the car with a VAG compatible scanner like VCDS while the problem is occuring - so that you can see the range selection in the scan tool and know if the ECU is seeing that the car should be in drive.

Alternatively, have a look at the range selection switch on the side of the transmission to ensure that it is damage free and the connections are sound.

Also, not a bad idea to check the TCU under the passenger front carpet - common for them to suffer water intrusion / damage and cause strange behavioural issues.

Sounds like the TCM put the trans in limp mode or something. There will be a DTC set in the TCM. Or, if for whatever reason there was an issue where the TCM did not power up, then the Engine will have a stored DTC for no communication with TCM.

You need a VAG specific scan tool to get any of this information.

This is what my gasser Passat stores for me when this type of thing happens:




No MIL on, and a generic scan tool will have no way of seeing this.

Windex said:

Weird one.

I suspect your car is an '04 - there weren't any 2003 TDI Passats, only 04 and 05.

The only way to be sure would be to (if no codes set) scan the car with a VAG compatible scanner like VCDS while the problem is occuring - so that you can see the range selection in the scan tool and know if the ECU is seeing that the car should be in drive.

Alternatively, have a look at the range selection switch on the side of the transmission to ensure that it is damage free and the connections are sound.

Also, not a bad idea to check the TCU under the passenger front carpet - common for them to suffer water intrusion / damage and cause strange behavioural issues.

Click to expand...

Ah yes, it's an 04. I own so much stuff, hard to keep track.

Water intrusion makes sense... I can sometimes hear water sloshing around in the dash when you make a hard turn early in the morning.. Not always though.

It's my daily beater, so aside from making sure fluids are changed. I don' t pay much attention to those things... Ha ha...

Maybe I should look for plugged drain holes.

No, you should look for a scanner.

I believe that sound of water sloshing around in the dash is so common it is considered normal. I have had it off and on going on five years and no negative effects.

Water sloshing around in the dash can also mean the drain plugs under the battery and vacuum booster are clogged and the tray is filled with water.

Once that water leaks past the cabin filter into the passenger footwell, the TCM wiring and connectors get corroded and the trams acts funny.

highmileage said:

I believe that sound of water sloshing around in the dash is so common it is considered normal. I have had it off and on going on five years and no negative effects.

Click to expand...

lolwut?? That's definitely not a common noise to have, the only fluid noises you should hear is when you turn the key just before you start the engine and the fuel pump kicks in.

As others have said it could be the TCM. Check your sunroof drains and remove the pollen air filter tray and see if it needs to be resealed, that's typically where water likes to get inside and ruin the floor, ask me how I know lol. As stated as well take the battery out and check the drains near it, i ended up removing the rubber stops because they were starting to deteriorate and were getting clogged too often anyways.

I would even go as far as to remove the TCM box and make sure its not filled with water. If your TCM is shot lmk I have one from my car before I swapped to a manual. I still have that trans to get rid of too haha

You should definitely invest in a VCDS cable though, makes your life wayyyyy easier

I think he means the heater core gurgle sound in the dash. My BHW did it from the day we brought it home brand new. Still does it, 190k miles and 13 years later. Many of the BHW cars do. My AWM cars never did.

I suspect that the EGR cooler's extra plumbing in the heater core circuit causes some air pockets to collect. It is so common that it seems to be a red herring. Some cars do it, some don't. But it is pretty common.

So long as the heat works, there is no coolant loss or anything strange like that, I would not worry about that noise.

Now sloshing back and forth, if the cowl drains are plugged up and the whole thing is fill of water (which could be GALLONS of it!) is for sure not good. You have to keep that area clean of debris every so often.

d0u8l3m said:

lolwut?? That's definitely not a common noise to have, the only fluid noises you should hear is when you turn the key just before you start the engine and the fuel pump kicks in.

As others have said it could be the TCM. Check your sunroof drains and remove the pollen air filter tray and see if it needs to be resealed, that's typically where water likes to get inside and ruin the floor, ask me how I know lol. As stated as well take the battery out and check the drains near it, i ended up removing the rubber stops because they were starting to deteriorate and were getting clogged too often anyways.

I would even go as far as to remove the TCM box and make sure its not filled with water. If your TCM is shot lmk I have one from my car before I swapped to a manual. I still have that trans to get rid of too haha

You should definitely invest in a VCDS cable though, makes your life wayyyyy easier

Click to expand...

I don't have a sunroof.

My battery area looks dry?

It doesn't always make that sloshing noise, but if it does it's usually only in the morning and for one turn? Kinda weird.


Coolant temp sensor just went bad this week, it could be a slow coolant leak allowing air pockets?

Haven't had the trans issue since, and I drive 100+ miles daily. Hopefully that doesn't happen again!

It kind sound like my car did; when cold, at times, there was a hard shift from first into second a "clunk" sound, like someone drove the gear in with a hammer. This went on for a while until my wife got stranded on a stop sign. She said there was a clunk sound and the car went into limp mode. After it was towed home I connected the vagcom and yes there were two codes (transmission related). I cleared the codes but the car would go immediately in limp mode if any attempt was made to drive it. My TCU had no water exposure. The transmission had only 30k miles on the overhaul and 12k on the torque converter. The original transmission died at 130K miles. Discussed, and removed the auto transmission and replaced it with a manual. After the the swap I was curious and removed the oil pan on the auto and found aluminum shavings and a few chunks of metal. There are some of us that have/had good luck with the tiptronic trany, I was just not one of them, I believe I have a lot of company. I like the manual transmission and hope to keep this car for a long time and maybe recoup some of the expenses. I love to drive the car but it has been a nightmare, the worst car I ever owned in 50 years of driving.

oilhammer said:

I think he means the heater core gurgle sound in the dash. My BHW did it from the day we brought it home brand new. Still does it, 190k miles and 13 years later. Many of the BHW cars do. My AWM cars never did.
I suspect that the EGR cooler's extra plumbing in the heater core circuit causes some air pockets to collect. It is so common that it seems to be a red herring. Some cars do it, some don't. But it is pretty common.
So long as the heat works, there is no coolant loss or anything strange like that, I would not worry about that noise.
Now sloshing back and forth, if the cowl drains are plugged up and the whole thing is fill of water (which could be GALLONS of it!) is for sure not good. You have to keep that area clean of debris every so often.

Click to expand...

Huh interesting, I didn't know that, still seems weird though. Also didn't know that area could hold that much water lol, damn

LKN said:

I don't have a sunroof.
My battery area looks dry?
It doesn't always make that sloshing noise, but if it does it's usually only in the morning and for one turn? Kinda weird.
Coolant temp sensor just went bad this week, it could be a slow coolant leak allowing air pockets?
Haven't had the trans issue since, and I drive 100+ miles daily. Hopefully that doesn't happen again!

Click to expand...

Only thing I'd say at this point then is to try and get a scanner and see if there are any stored codes. Ya never know.

d0u8l3m said:

Huh interesting, I didn't know that, still seems weird though. Also didn't know that area could hold that much water lol, damn
Only thing I'd say at this point then is to try and get a scanner and see if there are any stored codes. Ya never know.

Click to expand...

No codes and it hasn't done this since I replaced the coolant temp sensor.