My 2004 ZTS with 2.3l had exactly the same problem. In my case, it was the intermediate band, it was broken.
I took the car back out today to drive and get a better feel for the problem. It all boiled down to the fact I had NO 2nd or 4th (overdrive) gear. The part that could fail and directly cause that is the Intermediate band, it makes 2nd and 4th happen. So I was looking at the service manual and noticed that the intermediate band is the first item inside the trans from the driver side end. So I removed the lower mount and the upper engine mount, lowered the driver side a couple inches and removed the end plate of the trans. The band was cleanly broken about 2 inches in from one end. It slid right out. I put in a new one after soaking it for half an hour in fluid, put the cover back on, bolted everything back up and it drives like a new car. About a $30 part.... I took pictures as I went so I will try post them later.
This was my original topic thread below so you can see how I originally explained it:
Left work the other day and the check engine light came on as well as the OD light blinking. Won't shift on its own. P0767 code on the scanner, says stuck solenoid "D". Installed new solenoids, no difference but it now doesn't throw a code at all. Just wont shift......
Replaced the valve body tonight with a new one, no change at all.
The symptoms have remained exactly the same. Wind up in 1st, let off the gas and lets the revs drop down and it does shift, give it gas and all sounds fine. But jump on it and it winds up and freewheels. The OD select makes no change at all and manually shifting from 1st into 2 or 3 has no effect either. Nothing in the pan at all, it's clean. No noises either. So either something is physically broken inside ( broken band welds, busted drum etc. ) or some other sensor ( speed, rpm etc.) is bad?
99K easy miles, but a lot of mile. Had three trans fluid/filter changes during that 99K.
Last edited by 2004-zts; 07-16-2011 at 12:32 AM.
Reason: add more info