Originally Posted by LantanaTX
I have to agree with you. Even Rudy has told me they are not VIN specific. Model specific may not be the most accurate way to describe it. the reason the SRT TCU won't work in a n/a has to do with the difference in gearing in the trans and the different rear end ratio. I was in pretty constant contact with Rudy during his forst V8 conversion. Since he used the trans from a 55K car he had to use the TCU form the car as well as change the rear end to 3.07 There is a speed sensor in the trans. If the TCU thinks this speed is out of wack to the speed of the car you won't go very far.
BTW, Mopar has an upgraded Siemans TCU for the Hemi cars that use our trans. If the Hemi/SRT8 trans has the same gear ratios as the SRT and also uses a 3.07 rear gear, the mopar TCU just may work and is very reasonably priced. Other wirring would need to be verified but very worth looking into.
I spoke with Rudy on this issue after having problems with my TCU. The TCU from another SRT-6 will work in your SRT-6 "After" it has recieved a physical chip reset. This was only after trying 4 different SRT-6 TCU's in all three of my SRT-6 cars. All went limp without their own TCU installed.
32 Crazy - Your SLK appears to be somewhat different than the SRT's in my garage. I have also been working with Jerry resolving TCU issue over the past three months. He initially swapped my son and my TCU's while they were out of thier cases. When the incorrect TCU's were installed after the TCU mod, both cars went into limp mode. I am still working with Jerry to correct the TCU not holding gear and bouncing off the rev limiter issues. Jerry has explained that several TCU variations were available over the years causing inconsistancy in TCUs and TCU mod results.
Also, my cars will not upshift until they reach the correct RPM for the gear. If I am at 10MPH and select 5th the car will not upshift to 5th until the ECU/TCU agree that the car is at a safe speed. It will upshift through the gears as I achieve the next safe speed point.