Transmission or TPS

1996 4WD K2500 with a 7.4L, Started having what I assumed was transmission issues, because it started shifting extremely hard and would fail to shift into overdrive at times. I went to Autozone and had them scan the OBDII codes and nothing came up for the transmission. I did have a TPS malfunction code however, which I figured was unrelated.

While looking for rebuilt transmission online, I came across somebody with identical issues who also had a TPS code.

So, can my issues be caused by a bad TPS?
Would the transmission throw a code if it was malfunctioning?

Thanks in advance!

It sure could be a TPS issue. On electronic transmissions, the computer uses the inputs from the TPS to adjust line pressure in the transmission. The TPS takes the place of the TV cable in the older hydraulically controlled transmissions. If that TPS is spiking high its telling the computer that you are pressing on the accelerator which automatically increases line pressure which would in turn cause harsh shifting. Fix the TPS problem and your transmission problem should go away.

Let us know what happens.


transman

Problem solved. Put a new TPS in last night. Put ~100 miles on the Burb with no hard shifting. Significant difference in performance.

On a side note, if I ever meet the guy who designed the intake manifold on the 454 Vortec, I'm going to kick him in the head. TB has to be removed to get the TPS out... lame.