Originally Posted by Rabbitman
This might sound funny but I did the LMC5 a few weeks ago and the MGW shifter last week.
Did the original stock system actualy lock the transmission shifter too, I don't really remember if it locked or not and haven't had the car that long.
No. Only the steering wheel was locked.
The flaw with the original system that forced the NHTSA to demand GM recall the cars was that it was possible under certain circumstances to be able to drive the car with the wheel locked. Pretty scary that an unknowledgeable driver might actually attempt to drive the car.....
The recall service for manual trans cars reprogrammed the PCM to set the fuel shutoff speed to 2mph. So, when the column lock system (controlled by the BCM) "thought" that the column was locked when it ought not be locked, the BCM signaled the PCM to enable the fuel shutoff. The PCM then cuts off fuel when the vehicle speed reaches 2mph thus ending the joy ride of that unknowledgeable driver. Problem with that design is that the BCM does not actually know if the column is locked or not. It simply "logically" or perhaps more correctly " illogically" decides that the column is locked and acts on that judgement in requesting the fuel shutoff be enabled. Column might or might not be locked.
That is why devices like the CLB and later the LMC5 got developed to prevent the wheel from physically locking and to substitute aftermarket electronics that talked to the BCM fooling it into thinking the column lock system was working when in actuality the column no longer physically locks.