RS6 - torque convertor cicuit, stuck fault - advice needed

[ddillenger]

Hope my audi tech guy knows how that is done. I am assuming you are calling out a change to TCU programming.

If I do disable the TC lockup clutch, what will be change on up/down shifting and power?

I can confidently say that I am one of two people in the US that can do this. Yes, it is a change in the tcu programming.

As for change in shifting, none. Power, none, however the tcc will never lock, so there is waste there.

[agent5150]

I can confidently say that I am one of two people in the US that can do this. Yes, it is a change in the tcu programming.

As for change in shifting, none. Power, none, however the tcc will never lock, so there is waste there.

Nice. Hacking programming to work around the weakness. What does it do to the transmission in the long run. Am I buying time to deal with the expensive replacement or are you saying one can pretty much run without the lock as long as the tranny works

[ddillenger]

Running without the lockup will generate a bit more heat. HOWEVER, it will generate substantially LESS heat then a slipping converter clutch, and none of the particulate from the clutches winds up in your oil. You can run without the converter clutch indefinitely.

[lswing]

I thought the TC only locked when in cruising gear, usually 5th, maybe 4th, to be more efficient fuel wise?

I know that it's open when stopped, and in regulating mode when accelerating. I was under the belief that this slipping TC would also cause heating during this period since it can't accurately transfer power and is spinning extra. You also get the max torque through the TC during this regulating mode causing more issues.

Please correct me as I'd like to be spot on with this.

Daz, you in NY, Dyno, tune my car this spring?

[ttboost]

When my TC went, I was getting a 17125 code.

[lswing]

How? please do share.

also, I did the slip test, did not see or feel rpms rise without speed with curising at 50MPH in manual mode 5 gear. stays put a 1/2- 1/3 gas paddle. drops to 4th if I let it slow down.

Will be visiting my local audi tech shop to have to check to fault code again.

Good to hear. Get Ross-Tech, easily worth the $250, you can check everything and clear random codes, like an EVAP that could pop up.

Anyhow, you accelerated without noticeable slip, good. Maybe the problem is just starting, not full blown,
maybe random sensor. Mine didn't fail until 85k, with the last 10k having a powerful tune upgrade.

[DHall1]

This would be 100% correct.

Running without the lockup will generate a bit more heat. HOWEVER, it will generate substantially LESS heat then a slipping converter clutch, and none of the particulate from the clutches winds up in your oil. You can run without the converter clutch indefinitely.

[ddillenger]

Anyhow, you accelerated without noticeable slip, good. Maybe the problem is just starting, not full blown,

This is the most dangerous condition. When it all out fails it's no longer slipping, and not nearly as dangerous as it is when it sorta works (generating excess heat and sediment)

[lswing]

This is the most dangerous condition. When it all out fails it's no longer slipping, and not nearly as dangerous as it is when it sorta works (generating excess heat and sediment)

If it failed/locked completely the car would barely drive I would think, or be very rough. It has to open up to stop. Also, it's just fins in the TC I thought, no clutch disc at all.

[lswing]

If it failed/locked completely the car would barely drive I would think, or be very rough. It has to open up to stop. Also, it's just fins in the TC I thought, no clutch disc at all.

Nevermind, I used the Google, noticed the clutch pack for lockup in the TC. Still, to drive decent it has to open and regulate, so I think the OP's isn't that bad off.

[ddillenger]

Nevermind, I used the Google, noticed the clutch pack for lockup in the TC. Still, to drive decent it has to open and regulate, so I think the OP's isn't that bad off.

You are not understanding. It's naturally open/unlocked. It will never fail closed/locked.

The seals fail, there is no longer enough hydraulic pressure to engage the clutch properly, it ends up slipping. Imagine driving a manual with the pedal half in. Sure, it moves, but it's creating a LOT of heat, and wearing fast.

[lswing]

You are not understanding. It's naturally open/unlocked. It will never fail closed/locked.

The seals fail, there is no longer enough hydraulic pressure to engage the clutch properly, it ends up slipping. Imagine driving a manual with the pedal half in. Sure, it moves, but it's creating a LOT of heat, and wearing fast.

Got it. It threw me when you stated the fact that the OP's TC not slipping is worse. Under load his is transferring power just fine, and driving fine it seems, that's all.

[ddillenger]

The issue is it's not a binary converter (on or off). It's regulated, modulating the clutch.

So while it might not slip during steady state operation, It can easily be slipping during engagement.

[lswing]

If you do get VCDS from Ross-Tech, you can actively log/observe the TC function. It's interesting to see when it locks, unlocks, regulates. Forget which data block it is, but just log the data and keep an eye on your laptop to see it in real time.

[agent5150]

I was going to get the APR programming done, but with this TC thing, I am not sure if that is a wise move at this time. APR has dropped the price on it.. now $599... very tempting. And my mechanic keeps bugging me.. "no RS6 that I know, is running without it.. you don't know what you are missing" I thought... sure he wants me to get APR, it will probably shorten the life of turbos/tranny etc... more business for him :P.. but it was the price in thousands of dollars that always put APR at a lower prioirty for me.

[lswing]

I was going to get the APR programming done, but with this TC thing, I am not sure if that is a wise move at this time. APR has dropped the price on it.. now $599... very tempting. And my mechanic keeps bugging me.. "no RS6 that I know, is running without it.. you don't know what you are missing" I thought... sure he wants me to get APR, it will probably shorten the life of turbos/tranny etc... more business for him :P.. but it was the price in thousands of dollars that always put APR at a lower prioirty for me.

Yep, I'd wait until the TC is sorted out or cleared as good. That's a good price and seems like a solid tune. Any of the tunes will put a great deal more stress on the TC and Trans, usually looking at +50hp/+100tq at a minimum, adding to a gearbox that can break under stock power. Most of it comes down to how you drive it, or beat on it...I've been through one TC and two Trans, lesson learned with too much hard shifting.