I just rebuilt the transmission on my 96 Chevy Blazer. The second gear would slip around 2000 RPM then just rev as if in neutral. So I rebuilt the transmission myself. I followed a transmission rebuild manual to be thorough. The second gear clutch plates were obviously burned up. After reassembly, I test drove it with a little success. The second gear now works all the way to redline but won't shift into 3rd now. I checked and topped off the transmission fluid while it was running and hot. Still won't shift into 3rd gear. I'm thinking maybe there's a spring I may have overlooked in the valve body? Can someone point me in the right direction? btw the transmission type is 4L60E