I have a 98 Blazer with a 460le. When cold it shifts fine, as soon as it warms up the MIL light comes on and you get the PO785 code. PCM puts trans in high pressure and all you have is 2nd and 3rd. gear. Now this is the odd part, you pull over, shut engine off, wait a min. restart and the transmission shifts fine for the day, the MIL stays on though. I clear the code and everything is fine for the day. Next day a couple of miles down the road it starts all over again. I can skip the pulling over bit by clearing the code while driving down the with the scanner, once again all is well for the day. I always try to diagnois it properly from the start but being in a rush I tried the lazy mans way out (I hope nobody was offended by me saying that ) by replacing the shift solenoids but of course that didn't work, so before I replace the PCM does anyone have any sugestions?


Thanks for any help you can provide, Rick

 

http://ls1tech.com/forums/automatic-...785-4l60e.html

Page full of info there!

 

Here as well:
P0785 - Shift Timing Solenoid

 

Thanks for the links. Looks like it's time for me to study up again.

Rick