transmission codes ???
They report that there is a Ford TSB that states that the transmission goes into a "performance mode" if there are any detected fault codes. The performance mode includes increased line pressure and firm, sometimes neck-snapping shifts, especially from first to second. It isn't clear from the reports whether the fault has to be continuous or a one-time thing.
There are two common sources of "fault codes" that provoke this behavior. One is the manual lever position switch, which is a bank of resistors on the side of the trans that sense the position of the gear lever. As originally designed by Ford, this had a tendency to allow water infiltration, and Ford has a "retrofit kit". There is the obvious fault of the PCM thinking the lever is in some position other than it actually is (like neutral when you want "drive"), and also failure of "sanity checks" performed at various times. This problem has been mentioned as one of the things that causes "performance mode" aka hard shifts.
The other issue is with the RABS sensor. This creates a wheel speed signal which is used for the anti-lock brakes, and is converted to a VSS signal by the module that drives the vehicle odometer. The VSS is used by the PCM to determine, amoung other things, whether there is "excess torque converter slip".
You see where this is going. If there are any issues with the RABS or VSS, the PCM may flag a code 628, and then decide to put the trans into performance mode, which you then experience as "hard shifts". The code 628 in such a case is not real, merely a symptom of a faulty vehicle speed input to the computer. But the computer tries to "protect" the trans by switching to performance mode.
If you've changed the torque converter, let us hope it cured the problem. If it doesn't, you might look into getting the TSB on this issue and investigating the TSS signal.
Which I choose by checking with three service garages.
They all stated the transmission place I went to .
weeding out the useless ones in our area.
My most main concern is that it slams so hard when placing in reverse, from any place, neutral,or park. It seems like the rearend is going to take a beating, and sooner or later something has to give.
Only time will tell.
I have also noticed that the self test codes seem to differ from the codes read by a scanner.
Which does have me puzzled as to why they would be different.
Thanks again for all the research you have been doing on this problem.





