I bought a 2007 Crossfire Limited 2 months ago. It's in very good shape and appears to have been well maintained. I have been going through it trying to get ready for Ashville, NC rally.
I sent my RCM to Dj and my TCU ECU to MSS to get the tunes. I put it all back in, and now im having shifting problems into 3rd gear. No grinding just falls on its face and then kind of lunges on into gear. Thought maybe it was a re learning thing but has not cleared up. It wasn't doing this when I sent the TCU to MSS. I checked fluid level (80° C). I ran diagnostics and found historical codes which indicate speed sensor failure and limp mode. That tells me the conductor plate was probably changed. I saved the historical codes and then deleted them. So I can give the codes that were historic if needed. I put a new conductor plate in and did a full trans service. It's still doing it. Ran diagnostics again and have no codes. However, I was running live data (icarsoft mbii) on TCU and I noticed that one of the solenoids sits at 2 mA and fluctuates wildly upon downshift. Another sits at 0mA until downshift and is fairly consistent. The others stay consistent. Could it be Solenoid that shows different mA? Could it be the TCU or just bad transmission? I can wrench on cars and know my way around them, but these crossfires/mercedes are different animal. I dont know anything about transmissions. I have ordered 2 shifting solenoids. Anyone have any thoughts? Im kind of stuck.

 

I would call MSS and discuss it with them.

 

I have been working with Josh from MSS and he has been trying to help but those guys are super busy. It was recommended from someone I try here to help expedite troubleshooting.

 

You’re asking if it could be TCU or possibly transmission but HAVE you tried a different TCU?

$80 bucks on EBay and you’ll know or can rule it out within an hour of installation. Appears to Be an easy option.
you appear to be pretty deep into This already. What’s another $80 bucks just for peace of mind.

just my thoughts and it’s less than a night out with drinks. I hope you find a cost effective solution.

 

I ordered one shift solenoid last night and I am actually looking on ebay as we speak for a TCU. I'll try the TCU first and work from there. Like you said, I just hope it's a low cost thing.

 

I think replacing the TCU is a good option. From your post I could not tell if you had replaced the conductor plate. The speed sensor on the plate are a known failure point. Research Mercedes 722.6 conductor plate failures. While you got everything apart I would say replace the solenoid too.

 

I would not rule out the conductor plate. When mine was giving me issues it never triggered a code.

 

Yes i replaced the conductor plate. Ill wait for the TCU to get here and try that befkre dropping all of that again.