ok my transmission went out and i had it replaced and the mechanic told me there was a module on the transmission that only the dealer could reprogram for my car. well 2 months later i got the car back and im still having the same issues right before the transmission went out. now i know i need a new intake manifold and flapper and i have miss fire. now my question is. do the transmission or the computer for the car need to be reprogrammed, flashed or tuned or whatever? i dont know much so please dont flame me. im just trying to keep my car going.

 

The transmission doesn't need a tune per se. Any TCU (this is the module under the passenger side footwell) with the same PN can be swapped out. However, the individual solenoids that activate the hydraulics are tied to the conductor plate, both with respect to unit and position. The solenoids are bench tested during assembly and the the corresponding required values for each individual solenoid are written to what I think is something inside the conductor plate inside the transmission. I'm not even sure if a dealership can program this thing. I think normally they simply replace the entre conductor plate with every solenoid included as a single assembly, which is honestly what I would recommend based on my limited knowledge.

Hopefully someone more knowledgeable in this area can chime in.

 

That kinda sounds like BS.

 

I can try and clear things up, I am making my own TCM for the 722.6 auto gearbox, so have done loads of reverse engineering of the OEM TCM units.

NOTE: I am talking about the 722.6 gearbox here (AKA 5G-Tronic), if you have the 722.9 (7G-Tronic), then you are out of luck with swapping the TCM. It is part of the conductor plate and lives inside the gearbox. It is also married to the car and is part of the drive authorization process, so yes, only the dealer can change that for you.

Be careful with saying that the same PN can be swapped out. On the TCM there is data stored about your specific car (Called SCN coding). TCMs with the same PN can have different SCN coding. This coding can ONLY be changed via Mercedes' diagnostic tool at the moment (Or other high paid diagnostic tools).

If you are curious, the SCN coding string contains the following information (There is more, I just haven't figured it out yet!)
* Tyre circumference
* Rear diff ratio
* Engine type
* Transmission mechanical variant
* Transmission hydraulic variant
* Climate that the car operates in
* Torque converter damper inertia and resistance
* Shift paddles being present
* Profiles that are enabled (C/S/A/M/W)

If you can guarantee that a new TCM from a source (Such as ebay) came from the EXACT same car as yours (EG, A C200 CDI TCM going into another C200 CDI with the same PN), then yes, it will be plug and play!

This said, the stock TCM is absolutely awful at managing a worn gearbox. Which is something I am trying to fix. You can check my Youtube playlist here which is documenting the progress I am making on creating a brand new plug-and-play controller for the 722.6 boxes. I currently have a group of 30 or so testers helping me test this module in various other car configs, and so far, the results are EXTREMELY promising, giving a brand new lease of life to worn out boxes! There is a link to a form you can fill in on the more recent videos on that playlist if you are interested of testing this!

That said, can you describe what you meant by the gearbox 'let go'? There are loads of issues with the 722.6 which can all be traced to the poor software on the OEM TCM, If you describe what happened, I might be able to tell you exactly what is failing mechanically in the box.

Any other questions about the 5G tronic feel free to ask!