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The Mopar Performance SRT TCM does not work on my 08 300c SRT

6K views 12 replies 7 participants last post by  Hemissary 
#1 ·
Does anyone have a Mopar Performance SRT TCM, p/n P5155177, on an 08 300c SRT?

I bought one in june. It performed no different than a stock TCM. Stock shifts, and the Hold In Gear feature did not work. The car still up-shifted automatically in Autostick.

Has anyone else installed this and had it not work? All I want is the Hold In Gear feature.

This MTCM is advertised to work on 2005-2009 6.1's (as printed on the instruction sheet).
 
#2 ·
Was it brand new...or used?
 
#3 ·
i try a used one and a new one
 
#10 ·
i try a used one ,and a new one on my 2008 srt ,none of them work on my 2008 srt ,the used one work fine on 2006 srt.
 
#12 ·
Doesn't make sense; the used one appears to be offering changes that can be felt (by your reckoning). It therefore should offer the same changes in the 08' as transmissions / functionality are the same.

The new one...who knows what was done with it while in FCA custody. I bought a new and installed it for someone...it too operated like stock. An exchange resulted in a properly functioning unit.

Note that with the SRT; the changes are not as significant as the RT version, given the SRT OEM TCM already has less baby sitting and the marked tendency to revert to longer shift events.

How precisely are you installing the TCMs into the 08'?
back my Trinity to stock tune ,run until the transmission temp is between 140f and 158f,after i disconnect the neg battery and swap the tcm for the MTCM reconnect the battery and proceed to the procedure 4-5 coast down from 5th to 4th gear and then 4th to 3 th gear.for the upshift adaptation temp must be between 140f to 212f .from a stop i moderately accelerate the car to obtain all gear range while keeping rpm below 1800 ,i do that 5-6 times
 
#13 ·
back my Trinity to stock tune ,run until the transmission temp is between 140f and 158f,after i disconnect the neg battery and swap the tcm for the MTCM reconnect the battery and proceed to the procedure 4-5 coast down from 5th to 4th gear and then 4th to 3 th gear.for the upshift adaptation temp must be between 140f to 212f .from a stop i moderately accelerate the car to obtain all gear range while keeping rpm below 1800 ,i do that 5-6 times
That will not work with a / any used TCM. Existing (stored - non-volatile) data needs to be purged using a StarSCAN / MOBILE / WiTech or other Diagnostic Tool.

I'll assume you already know and followed the following as specifically laid out in the Instructions; with a brand spanking new units, they are set up to automatically begin measuring and storing data. As temperature rises from one measuring threshold to the next, brand new TCMs commence storing the next version of specified parameters.

I was wondering about the exact procedure you used to ensure the new or used MOPAR Performance TCMs are not being overwritten with the stock TCM file that is stored in a / any hand-held when a tune has been loaded. This is usually the scenario that bricks MOPAR TCMs; returning to stock with the MOPAR TCM installed.
 
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