You are experiencing the EXACT same symptoms I had, although mine was more intermittent than yours. See this thread. Explains the whole issue. Contacts on conductor plate move around and speed sensor loses connectivity. Harsh shift occurs, goes into limp mode, stays in 3rd gear, no supercharger.... you turn it off, let it cool, and it improves. Check your codes to see if any are related to speed sensor or other issues related. For me, it was the speed sensor contact losing connectivity the most. There are other contacts there that may also wobble and give different codes.

When doing the tranny fluid, do NOT use ATF+4. Shell ATF134 is specifically suited for the Crossfire and it's listed right on the label of the tranny fluid bottle. Watch the video. It's pretty self-explanatory. If you were low on fluid, it may give different issues (my connector was leaking also, changed that first, but it did NOT fix the overall issue). So, assuming fluid level is OK, do the fluid fix first. Or, just go for the whole nine yards and just change the connector, O-ring, and the conductor plate. I got my whole kit with connector, ring, gasket and conductor plate on Ebay for $77 total from some Mercedes Benz place in Phoenix, AZ. See the second link for the old listing, while it still exists

Video that describes in detail contact issues on conductor plate

https://www.crossfireforum.org/forum...tml#post875686



Conductor plate kit: germanpartsaver on Ebay (Phx, AZ), $77, free shipping

http://www.ebay.com/itm/281509287166?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT