Hello everyone
I have been picking your brains for awhile, but now I'm stumped. I have a “bargain” 1997 blazer I got with a blown engine it has 180,000 miles on it.
After rebuilding the engine and chasing all the gremlins out of the engine I'm left with a transmission problem. Here's the details.
When first cranked up and driven everything works fine the trans shifts up and down just like it should.
But when it warms up it goes into “limp home mode” I get second and third but only when I manually shift also I get a code P0785. Here's what I've done so far.

• Changed the ignition switch
• Replace 3-2 downshift and both shifting solenoids
• Checked the wiring harness and fuses

I've read everything I could find most of it says the transmission is toast.
But it SEEMS TO ME that I have a pressure problem that when the transmission warms up and the fluid thins out and I'm loosing pressure somewhere.
Sorry about the rambling but I wanted as much background before I asked my question.
Do you'll think it would be worthwhile to change out the valve body the spacer plate and check ***** to try and address the pressure problems? Or should bite the bullet and change out the transmission?
I'm in Atlanta and we have a junk yard called Pull a Part I can get a transmission for around 70.00 dollars with a 30 day guarantee a valve body with a pan will cost me 15.00 so at that cost I'll throw used parts at it. As I understand with a 1997 transmission I can use 97-04 is that right?
One more thing I think the transmission has been changed out so its mileage is unknown.
Thanks for all you advise and help that I have received so far from this site.

 

Let me start out by asking that you do not modify the font size of your post. That is mighty hard to read on my high resolution monitor at work...

About your problem. Since you have an active code, I would start there:
P0785 - Shift Timing Solenoid

If you cannot make it through the entire diagnostic tree, you may have to take it to someplace for a proper diagnosis.

 

It goes into limp mode but the fuse is good that powers the trans? Sounds like there is at least one more gremlin to find. Sounds like a broken or frayed wire somewhere.