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Thread: Transmission Behavior Question

  1. #19
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    The TCU is really a 1 banana job. Maybe even a 1/2 banana. It's under 5 minutes, and that's if you go slow. If you are an engineer, this would fall into the 1st semester, intro to freshman physics class.

    Quote Originally Posted by PixieVC View Post
    Oh boy. I knew taking certain liberties would come back to bite me. The car will be serviceable at the time I decide to let it go. I made a huge investment in the car, above the price of purchase, to ensure that it'll be working well for me for at least a few years. Per your comments, I've gone ahead and decided to dump the several hundreds of dollars on a computer interface for the car so I can... look at a stream of numbers and try to determine if there's a problem. Fortunately pattern recognition happens to be my personal piece de resistance as an engineer and analyst, so I should be able to have this figured out in no time.

    MTM TCU, huh? I really don't want to rip up the carpet for that... anyone know of a shop or a man I can pay here in the SF Bay Area to handle these sorts of things for me? Doing the computer upgrades, for example...

  2. #20
    Registered User 4everRS's Avatar
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    Pixie, I have bad news for ya. You will be spending much more on this car as time goes on. I consider it a pretty high mainanence car when compared to normal cars. And even the regular maintenance is much more expensive than a normal car. You ought to have a couple thousand in savings just dedicated to car issues. That or the cash flow to be able to sustain a financial hit when something like the tranny shits the bed.
    Avus Silver RS6 - Viper Stage 2 ECU/TCU - Water/Meth Injection - Frozen Rotors - Hbars - clear corners - Hella smoked tails - gutted precats

  3. #21
    Registered User PixieVC's Avatar
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    Quote Originally Posted by 4everRS View Post
    Pixie, I have bad news for ya. You will be spending much more on this car as time goes on. I consider it a pretty high mainanence car when compared to normal cars. And even the regular maintenance is much more expensive than a normal car. You ought to have a couple thousand in savings just dedicated to car issues. That or the cash flow to be able to sustain a financial hit when something like the tranny shits the bed.
    I have a $5,000 slush fund for the car. I figure that should cover the bases for anything short of my engine blowing up...
    Daily Drivers: 2002 Mercedes E55 AMG, Brilliant Silver, Autoadapt Menox control, hard-wired Valentine 1 | Ki Tsunami Titanium w/ Spinergy SPOX, Jay J2 Seatback, Jay J3 cushion, 2.5 degree camber

  4. #22
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    The $5k will hopefully hold it. Most of my servicing has been under that, but this last one was $7200, and the one before that was $9100, i believe. The last one was valve cover gasket, 4 injectors, temp sensor, timing belt, water pump and cv boot. can't recall the other. I think i blocked it out of my mind from the pain.

  5. #23
    Registered User hahnmgh63's Avatar
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    In my case KWV3's to replace the crappy recall DRC and the Revo / MTM software and that is it except engine, diff, and tranny oil changes and rotors which thankfully I do all myself. That is until, my own fault, I broke the downpipe stud not being careful enough trying to remove them to gut them. Now I dumped $8K into the car, tranny/TC, Turbo Rebuild, hoses, seals, all my labor. None of this had to be done I just figured while the engine is out make it all equal or better to new. Maybe my car was a midweek production and they weren't hungover on Monday or looking to get off work on Friday and didn't down too many liters at lunch while they put it together as it's been very reliable (I'm looking for something wood to knock on right now since I said that). I'm looking for another 5+ years of reliability with a trans that shifts better than stock.
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  6. #24
    Registered User mik15's Avatar
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    since we're talking about money...only bought the car less than 3 weeks ago and already spent 5k and it's not yet as i want it to be but at least i did the important jobs like the DRC and T-belt so hopefully at least for a few months from now on i won't have to spend again too much money ...hopefully!

  7. #25
    Registered User ttboost's Avatar
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    Disconnect both battery cables from the battery and touch them together for about 10 seconds. hen go drive it and see if it changes. Sounds like maybe your TCU is stock. The MTM TCU chip is a MUST for these cars. Not only will you get better shifts and drivability, you will prolong the life of your transmission (especially if you upgrade the TC too). Might cost a couple bucks, but will go long and far in helping you enjoy your RS6 experience....otherwise you will be in for a new transmission soon, especially if your ECU is flashed.

    As I have said before... you REALLY have to love Audi's and love THIS car, to put up with some of its shortcomings...and if you can't wrench yourself, you will spend a decent amount paying someone else to...
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  8. #26
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    Yeeks, were these out of pocket service costs or extended warranty pick up the tab?

    What switches do you need? I have stash.

    Quote Originally Posted by peiserg View Post
    The $5k will hopefully hold it. Most of my servicing has been under that, but this last one was $7200, and the one before that was $9100, i believe. The last one was valve cover gasket, 4 injectors, temp sensor, timing belt, water pump and cv boot. can't recall the other. I think i blocked it out of my mind from the pain.

  9. #27
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    Pulled TCU and fairly easy to do with only 2 screws holding the kick plate, pulling up the plastic sill plate and prying up the carpet enough to pull the plastic TCU box. Take the plastic cover off and pull 2 more screws to get the aluminum TCU cover free. Connector is a cam over lock that rotates off. Now when I took the plastic cover off, the top of my TCU cover fell off. Apparently, it has been apart before as the tabs are all broken off. Can anyone look at the TCU board and tell me if it is stock or has a chip? The chip in the upper left has a label on it and doesn't appear to be a factory solder job. I pulled the TCU because of shift problems (coming out of gear under WOT).

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  10. #28
    Registered User kday's Avatar
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    905084, I don't know if you're chipped or not -- hopefully someone else will recognize that label -- but could you do me a favor while you have the TCU out? Assuming you have an meter that can measure resistance, otherwise never mind.

    I am curious to know what the resistance is between the two CAN bus pins on the TCU. This can be done with the TCU on the bench and unpowered. The two pins are 85 and 86, which are most likely labeled on the connector with very small numbers.

  11. #29
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    Sorry kday, just chucked it back in to take for a spin and see if the contact cleaning helps my shifting problems. I'm sure it will be out sometime i the near future though. What do those pins do? Don't want to ohm out something a fry a chip, but happy to help if I can.

  12. #30
    Registered User kday's Avatar
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    Those pins are the TCU interface to the powertrain CAN bus, which connects the ECU, TCU, ABS, steering angle sensor, instrument cluster, and (maybe) HVAC head. It's essentially a computer network, not that different from an Ethernet you might plug your PCs into, but optimized for reliable real time transfer of small pieces of data. In this case, things like engine speed, gear selection, etc. Instead of running discrete wires around the car carrying e.g. the tachometer signal, like in the old days, the ECU sends a data message periodically, and any interested control units will receive it.

    At the electrical level, the bus is what is known as a transmission line, and one property of transmission lines is that they must be "terminated" at each end with a resistance, in order to prevent signals from being reflected from the ends of the bus. These reflections can corrupt data. I want to verify that the TCU is not terminating the bus. The Bentley manual suggests that it is not, but the Bentley has been wrong before. This is relevant for those of us looking to replace the automatic gearbox with a manual. If the TCU were terminating the bus, its removal could cause bus errors. And in fact there are CAN bus errors present in the 6 speed converted RS6 that I know of. This is a long shot but wouldn't it be funny if a resistor costing a fraction of a penny could fix those issues...

    If the TCU is terminating the bus, there should be 120 ohms between pins 85 and 86. If not, the resistance will be much higher.

    No worries if it's not conveniently accessible.

  13. #31
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    The CAN bus must be like an Arinc 429 bus in aircraft I assume. I'll check it next time it's out. Had the beast out for a spin after contact cleaner on the TCU and it didn't miss a shift. Still had the MAF implausible signal and banks 1/2 running lean so it's time to find a leak i would guess.

  14. #32
    Registered User kday's Avatar
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    I wasn't familiar with ARINC 429 until I just looked it up on Wikipedia, but yes, it is very similar.

  15. #33
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    905084, can't tell if your tcu is chipped. I doesn't look like it by the solder work. Looks original. I've been wrong before.
    Avus Silver RS6 - Viper Stage 2 ECU/TCU - Water/Meth Injection - Frozen Rotors - Hbars - clear corners - Hella smoked tails - gutted precats

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