I have a 1997 blazer. When first started in the morning, the charge meter is past the middle line just to the right. Shifts smooth as butter. But after driven for 10-15 minutes, it starts shifting rough, and does not want to go into low gear when I stop at a light or whatever. I have had the alternator changed. It registered a 785 on uncles computer. He said that was a shift selenoid. Could it be something other than that? Based on what I'm describing here? It is an auto transmission.

I've read people have had similar problems with this year of
Blazer.....

 

https://blazerforum.com/forum/diagno...plained-28394/


CIRCUIT DESCRIPTION
The 3-2 Shift Solenoid (SS) valve assembly is a normally-closed, 3-port, on/off device that controls the 3-2 downshift. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through circuit 1020. The Vehicle Control Module (VCM) controls the solenoid by providing a ground path on circuit 687. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The VCM varies the timing between the 3-4 clutch release and the 2-4 band apply, depending on the vehicle speed and the throttle position.

When the VCM detects a continuous open, short to ground or short to power in the 3-2 SS valve assembly circuit, then DTC P0785 sets. DTC P0785 is a type A DTC.


So in addition to a potential electrical problem with the 3-2 SS, wiring could also be causing a P0785. Read the link for full diagnostics.


I'm guessing a good tranny shop could take care of this pretty easily. You might want to consider that.


Doubt that a 4L60e problem is limited to a certain year of Blazer. Beware of the "this is what fixed mine" Internet fixes.