99 Silverado 1/2 ton 2wd, 5.3L 120,000 miles, No mods what-so-ever. Kicked a cel and trans went into limp mode out of nowhere. p0785 3-2 solenoid circuit. Pulled pan, turned key to on, grounded solenoid, barely clicked, started to smoke. Others all clicked good and loud. Replaced with new GM part, Tested with ground wire again, acted like it should.

Put it back together, and still in limp mode. Thought maybe it would self test (Im by no means a transmission pro) Pulled scanner out, reset computer, shifted like a dream, better than before.... for about 2 miles. Light comes back on, back in limp mode. Reset light, shifts fine for a while again, over and over. New code is p0758 Solenoid B circuit.

I don't want to tear this thing down a hundred times and put all this money into it if its something deeper than the solenoids. Looking for opinions from the trans guys. Did put in new fluid and filter with first solenoid. So is it just coincidental that this one quit at the same time? Or am I looking at something more serious? When you reset it, sometimes you'll get several miles out of it before it kicks the light back on and back into limp mode.

Im 99.9% sure I didnt knock any plugs off when puttin pan back on, Looked in with a flashlight after I got it up in past the exhaust, before I put it all the way up. And I'd think it would kick the code immediately, all the time, if I had knocked one off.

 

Maybe the valve body is worn and the valves are sticking. We got a couple good tranny venders here though which will probably help you out sooner or later - or maybe you can PM the Performabuilt guy. He seems to offer a lot of detailed advice to people who need it.