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View Full Version : 4L80E Shift switches , Question



rjwest
07-01-2004, 06:08
As I understand: The Manuel Shift lever closes/opens a set of 3 switches, which tell the pcm the position the Shift lever is in.

? Does the movement of the Shift lever from OD to
third do anything else.? Does it force the shift or just tell the PCM to make the shift?

I see there is a code sent to the pcm, If I open the Line to the PCM that indicates a OD position,
and makes it look like the lever is in 3rd gear,
will the transmission shift to 3rd,,,,I would like to be able to downshift without " grabing the lever" all the time...

I usually Manuel shift to 3rd when starting up a hill where I now the truck will down shift to 3rd,

If I shift ahead of the computer shift, I can get an " unloaded shift into 3rd and TCC will lock
up without load, than pull hill in 3rd gear with
TCC locked....I do this when I have my truck camper loaded.