Trans goes into a mechanical fail safe. I think it’s 4th and reverse that works only. If your tcm was infact the problem. It should go away after unplugging the harness.
If you unplug it and things work properly (shaft stops turning while in Park), it won't still turn the input shaft. So if the shaft stops turning after unplugging the TCM, the TCM was trying to command it. Not likely to be the case. If they unplugged it while the shaft was still trying to turn in spite of being in park, then it's a mechanical issue making it still pull. This is the likely case.
If it is fixed now by whatever they did, that means the shaft isn't spinning while in park so it should stay that way if you disconnected the TCM. Then it would default to only having 4th or Reverse when shifted into gear with the TCM disconnected.
Thanks guys for clarity.
They say it is fixed with this excerpt from an email:
"THE TRANSMISSION INTERNAL ELECTRONICS CHANGED WERE, THE PCS(D),PRESSURE MANIFOLD SW,& INTERNAL HARNESS ASSEMBLY. THERE IS ALSO A NEW MLPS IN PLACE WHICH WE CHANGED EARLIER (A KNOWN PROBLEM/ISSUE ON THIS PLATFORM). I DO RECOMMEND LEAVING IT IN PLACE AS EVERYTHING IS WORKING WITHOUT ISSUES AT THIS TIME."
I have an email stating 2 weeks ago that the MLPS made no changes to issues with 2nd transmission, though in quote above, they say it did...
I asked them to run this test we are discussing anyways, just to make sure we have no hidden issues, but they are reluctant to at this time, since they have put roughly 100 miles on this transmission after quoted fix above, and testing 4hi and 4lo shifting with no issues, and want me to come get the truck...
