The trans can go "limp home" for a huge number of reasons. Lack of speed signal from the traction control is one, improper shifter inputs one, alternator voltage too high or low, CAN issues another, tires the wrong size another. But, the point is that diagnostics produce results or guesses. Intermittants don't leave much to test, but they do leave codes. There must have been codes to throw the parts that have been thrown, what were they?

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician