454hemi

This theory sounds good. Could it be that the A shift solenoid gone bad without raising any error code ?

I scan my car via GM Tech 2 and found brake switch open circuit trouble code. After that I replaced brake switch to new one.

Hi everyone, I have a problem with my 4l60e tranny in my 96 Chevy Tahoe 5.7L Vortec. My trans won't shift to 4th gear. When I put shifter into overdrive position and start acceleration trans normaly shifts through 1-2-3 gears. After that RPM goes to 3000 - 3100 but car won't accelerate no more and I get 62 mph and 3000 - 3100 rpm. In shown in this video. https://www.youtube.com/embed/t0zkwD9MMd4 In good case when all work fineI have 80 mph at 2500 rpm. https://youtu.be/hAd4f2r_9sQ After diagnostic I replaced TPS sensor and brake switch, but problem won't go away. What could be the problem ?