[Mish_Mish]

I may be out of sequence here. Is this after they swapped the fluid, wiring harness and valve body or is this pictures of that service?

Yep, all these did not fix the erratic 3rd gear, so new gearbox is their next step.

 

[Eleven]

Is the TCU part of the transmission swap? If not, then I'll bet you will see the same issues in a month or two, even though you have eliminated every other variable, including fluid, valve body and wiring harness, except the box telling the transmission what to do.

If it is part of the transmission swap, see if they will put the old TCU in first and test to see if you have the same drivability issues. Then, swap out the old one for the new one and see what changes in the shifting behavior.

You really have a unique case in that with a little additional testing, we can finally get down to the cause of the sloppy shifting. A lot of questions will be answered.

I know I would rather change a TCU and know it is going to address the symptoms than change a valve body, fluid, and finally transmission and still have the same behavior.

 

[Mish_Mish]

Is the TCU part of the transmission swap? If not, then I'll bet you will see the same issues in a month or two, even though you have eliminated every other variable, including fluid, valve body and wiring harness, except the box telling the transmission what to do.

If it is part of the transmission swap, see if they will put the old TCU in first and test to see if you have the same drivability issues. Then, swap out the old one for the new one and see what changes in the shifting behavior.

You really have a unique case in that with a little additional testing, we can finally get down to the cause of the sloppy shifting. A lot of questions will be answered.

I know I would rather change a TCU and know it is going to address the symptoms than change a valve body, fluid, and finally transmission and still have the same behavior.

I asked them about TCU, because it was natural that it causes bad shifting, however they said that it had been re-flashed and acts perfectly normal, therefore VW thinks that TCU is fine. I also requested to purchase new unit, if they decide not to replace it, thinking that old one will kill my new transmission. One way, or the other, same gearbox is used on: Lexus LS430, Mustang Cobra and some other vehicles and none of them suffer from bad shifting...

 

[Eleven]

I asked them about TCU, because it was natural that it causes bad shifting, however they said that it had been re-flashed and acts perfectly normal, therefore VW thinks that TCU is fine. I also requested to purchase new unit, if they decide not to replace it, thinking that old one will kill my new transmission. One way, or the other, same gearbox is used on: Lexus LS430, Mustang Cobra and some other vehicles and none of them suffer from bad shifting...

That does not make any sense. I think there was a post here about somebody changing out his TCU and it resolved the issues he was seeing. Sounds a lot cheaper than a transmission.

Anyway, I agree with your assessment. These transmissions have been in use in other applications for a long time. Failure rates for components is known. In addition, Aisin probably knows how to make a transmission, and has the component selection and design pretty much ironed out.

If it was a mechanical failure, then I would think it would do it all of the time. If occasionally, then I would look at a control mechanism, like the valve body, which was already replaced in your case. Of course, the only other variable left is the TCU, the only thing the VW dealership assumes is working properly.

Besides doing a flash, which doesn't prove anything is working, how do they know the TCU is working properly? Did they test it? If so, how did they test it?

Sorry for all of the questions - this is very interesting to me.

 

[Mish_Mish]

That does not make any sense. I think there was a post here about somebody changing out his TCU and it resolved the issues he was seeing. Sounds a lot cheaper than a transmission.

Anyway, I agree with your assessment. These transmissions have been in use in other applications for a long time. Failure rates for components is known. In addition, Aisin probably knows how to make a transmission, and has the component selection and design pretty much ironed out.

If it was a mechanical failure, then I would think it would do it all of the time. If occasionally, then I would look at a control mechanism, like the valve body, which was already replaced in your case. Of course, the only other variable left is the TCU, the only thing the VW dealership assumes is working properly.

Besides doing a flash, which doesn't prove anything is working, how do they know the TCU is working properly? Did they test it? If so, how did they test it?

Sorry for all of the questions - this is very interesting to me.

I already told you what I know, I will talk to service manager when I get the car back. It is delayed for 2 more days, because some connector between transmission and TCU looked bad to them and they ordered new one.

At this point, I will go with the flow and let them spend more money, if they insist.

 

[Luzy V8]

........ I think there was a post here about somebody changing out his TCU and it resolved the issues he was seeing. Sounds a lot cheaper than a transmission......

I guess you mean me. The TCU replacement helped, but it did not resolve the problem completely. That was btw AFTER my first transmission was replaced, because of slipping gears and harsh up/downshifts. I was/am still not fully satisfied with the shifting quality of my second transmission, but it isn't that bad that I would spend any significant money on it (yet).

 

[Eleven]

I guess you mean me. The TCU replacement helped, but it did not resolve the problem completely. That was btw AFTER my first transmission was replaced, because of slipping gears and harsh up/downshifts. I was/am still not fully satisfied with the shifting quality of my second transmission, but it isn't that bad that I would spend any significant money on it (yet).

Yes I did.

Just thinking out loud here but is the TCU hardware the same across all applications (Porsche, Audi, etc...)? In other words, is it supplied by Aisin or does each manufacturer supply their own hardware using the specifications supplied by Aisin and then supply the code? Maybe it ids from a third supplier and they all use the same TCU hardware. Id on't know, but it would be interesting finding out.

 

[Mish_Mish]

Yes I did.

Just thinking out loud here but is the TCU hardware the same across all applications (Porsche, Audi, etc...)? In other words, is it supplied by Aisin or does each manufacturer supply their own hardware using the specifications supplied by Aisin and then supply the code? Maybe it ids from a third supplier and they all use the same TCU hardware. Id on't know, but it would be interesting finding out.

Will pull and look, as soon as I get my fat, dealer dwelling, whore back!

 

[v10treg]

My V10 would Downshift really hard, and "Bang" into gear.... It would also do it for the dealer when they test drove it... Their first fix was to replace the valve body, and update the TCM... The problem still persisted. They replaced the entire transmission with a new one (lucky me). But usually, a valve body replacement fixes that problem in the 04 v10s. BTW: a new tranny is approximately $10k CAD + Labour (Thank god for powertrain warranty)... I will change the fluids every 50,000km regardless of what they say about "lifetime fill".

 

[Mish_Mish]

Yes I did.

Just thinking out loud here but is the TCU hardware the same across all applications (Porsche, Audi, etc...)? In other words, is it supplied by Aisin or does each manufacturer supply their own hardware using the specifications supplied by Aisin and then supply the code? Maybe it ids from a third supplier and they all use the same TCU hardware. Id on't know, but it would be interesting finding out.

Here is the latest scoop, new transmission is in and it still does the 3rd gear slip!!! Service manager called me today stating that they are on the phone with service adviser from VW, probably going to replace the TCU as well (I think).
So, new transmission does not fix the slip, let's see what does...

 

[Mish_Mish]

So now I am waiting for the TCU to show up and hoping it fixes the funky 3rd gear syndrome. It has been weeks in the shop and driving old Audi, but this is all for the best.

 

[Eleven]

What else is there to replace?

Seriously, I assume the new trans includes a new torque converter, so what else does that leave?

My truck goes in for the 40,000 service tomorrow. I still get the 3rd gear slip, hunting and thumping, and some other, intermittent shifting issues that I can't replicate in front of the dealer.

I really don't think there is a mechanical issue with the transmission. Too bad we can't switch off the DSP (shift learning) for testing or at least reset it.

 

[Mish_Mish]

What else is there to replace?

Seriously, I assume the new trans includes a new torque converter, so what else does that leave?

My truck goes in for the 40,000 service tomorrow. I still get the 3rd gear slip, hunting and thumping, and some other, intermittent shifting issues that I can't replicate in front of the dealer.

I really don't think there is a mechanical issue with the transmission. Too bad we can't switch off the DSP (shift learning) for testing or at least reset it.

Yes, converter is new, still no help.
Will find out progress tomorrow, but i am getting a little irritated by having my car in service for 3 weeks now.

 

[Eleven]

I found a fix for the poor shifting - don't leave the dealership parking lot.

I drove it around with a tech and a vag tool today in an attempt to replicate the problem and it shifted perfectly.

Back to the drawing board.

 

[Mish_Mish]

I found a fix for the poor shifting - don't leave the dealership parking lot.

I drove it around with a tech and a vag tool today in an attempt to replicate the problem and it shifted perfectly.

Back to the drawing board.

My third gear seems to like dealership, it really opens up to them and shares its problems
Currently I am waiting on TCU from Germany, however I have slim hope that it will fix it.
Another idea, re-flashing the ECU, I think engine controller is screwing up the shift pattern, because when it happens it seems to rev up to about 3700rpm, but not the red line and then act like rev limiter kicked in. It has to do with either engone control mapping, or fuel starvation of some sort. :writers_block:

 

[Mish_Mish]

Just heard back from dealership, it seems as though new TCU fixed the 3rd gear slippage, but there is still some kind of RPM cut off at 3700-3900 rpm, so we will see when I drive it tomorrow. They say that this cut off is triggered by torque limiter in engine controller, at least that is what VW says. Picking her up tomorrow, cant wait!

 

[Mish_Mish]

Well, it has been 8 weeks now and she is going strong. Shifting is a lot better and if I did not know of 3-4 issues, I would not notice anything at this point.

 

[Eleven]

Hey Mish_Mish, I was just thinking if the trans replacement addressed your shifting issue.

I've had mine in the shop a couple of times, and even after producing a repeatable test that demonstrates the symptom, they found nothing wrong with the shifting.

Figuring this was a dead end, I went ahead and swapped the transmission fluid at 43,000 miles. All of my other vehicles get fluid changes because I believe ATF is a wear item, so why not the Treg?

Anyway, I'll give it 1000 or so miles and see if it was a good move or not.

Last thing I am looking at is somehow resetting the TCU back to 'day one' by clearing out the history. Perhaps it learned a bad habit or two.

 

[Mish_Mish]

I believe there are ways to reset transmission via Vag Com, or even with some other sequence.
One more suggestion might be, getting diagnostics from independent shop and based on that filing small claims law suit, that would get VW's attention on the matter, if local dealer keeps jerking you around.

 

[tourrig]

Hey Mish_Mish, I was just thinking if the trans replacement addressed your shifting issue.

I've had mine in the shop a couple of times, and even after producing a repeatable test that demonstrates the symptom, they found nothing wrong with the shifting.

Figuring this was a dead end, I went ahead and swapped the transmission fluid at 43,000 miles. All of my other vehicles get fluid changes because I believe ATF is a wear item, so why not the Treg?

Anyway, I'll give it 1000 or so miles and see if it was a good move or not.

Last thing I am looking at is somehow resetting the TCU back to 'day one' by clearing out the history. Perhaps it learned a bad habit or two.

How did your transmission oil change work out? My v10 now has 140k and I wonder if I should change the fluid.

Thanks