terrymargate

I have a 2011 W221 transmission with a fault.

The shop that has it tried another transmission today (form a 2007) and said it was not even recognized

I'm thinking they may not have too much experience with Mercedes despite their initial pitch :-)

I know the TCU (electronic shift module) is a theft relevant part and I need to use my original one, but if I get another transmission from another simialr W221, should it just work (I know it will require adaptation, I have star)

OR... are there any other VIN coded parts, ie the valve body?? I have looked online and find conflicting views

Thanks for any advice

Diesel Benz

Since you have Star, make full use of it and read WIS instructions for transmission service and run DAS simulator to see the steps for transmission related coding and you'll find it impossible to swap the tranny (assuming your private Star tool is the only tool available).

terrymargate

Oh No!!!, that is dreadful news, I just ordered a nice used tranny with only 12000 miles and 2012

Can you tell me what prevents it being changed pleased? (assuming I use my original ECU) Is the valve body coded? and can it be recoded, if not can I use my original valve body? (assuming its OK)

I had the engine changed recently and it worked a treat, simply used the ECU from my original engine

Would be great to know what prevents the trannys being changed, I assume all the hundreds on the market are not bricks, so is it something an original star can fix? If so I will take it to a garage that has specializes in Merc transmissions to have them do the swap

thanks again for help and advice

Smalone01

As long as your original valve body and electronic shift lock is ok then just swap your old parts into the new used transmission.

Speedriven1

On the V8's you cant. The tcu is part of the valve body and is vin locked. The only way to do it is if you swap valve bodies from original to the new one.

Smalone01

This is what I was trying to explain. Technically you could switch tcu from the old valve body to the new (used) valve body I believe. As long as neither are really old.

terrymargate

Thanks for the replies, will try to use original valve body

if it does need changing, how do they do it with used ones? can it be coded with star (online), or does it have to be a virgin valve body then coded to vin by dealer??

Speedriven1

If original valve body is good(working perfectly) it should be a plug and play no coding.

terrymargate

just spoke to a seemingly knowledgeable place (autobahn performance) down in Ft Lauderdale.

They said in the event that the valve body had a fault but electronics could be read, then it was simply a matter of reading the coding info into star with old valve body connected, installing replacement valve body and then programming it with the old info

does that sound correct? and can this be done with normal star or does it have do be done online (I have access to both, just curious)

I got another transmission in the UK as they are way too expensive here in Florida and am having it flown to Miami, just trying to get things ready for when it arrives to prevent any problems

Speedriven1

Coding can be transferred, if their equipment is dealer spec

Nickthegreek

What you are referring to is called SCN coding. It is made so that you cant put stolen or nonapproved parts in it. When you code the tcu it is locked to that vin only. Only dealers or indy shops with an account through mercedes can do this. If you were to buy a new "virgin " state tcu that has never been programmed then you can just transfer the info from the old one to the new one without needing scn coding.