1993 C2500 X-Cab 2wd 190K lifted the hood and found a Rat starting a nest right behind the filter. Cleaned it all out and to my surprise could not find any wires chewed on (not so lucky with my VW) turned over slow so I jumped started. Pulled out of the drive and BAM, BOOM, BANG revs through the ceiling! Very hard shifts when it decided to shift. The tranny has never given me a hint of an issue. Pulled the pan, looked fine. Flushed with 18Qts some improvement but no luck. Checked both speed sensors, clean, all connection and grounds, all look good? 14+ volts at both batts while running? Checked TPS. 3.8 volts at idle and voltage all over the place through throttle stroke. Auto parts stores no luck for a TPS so I went to dealer and got a replacement. I set it up at, .6V at idle, good range trough stroke to full throttle and I believe it was 4.? (the paper I noted it on is in the garage) Took truck for drive and all seems to be back to normal!! Good day. And thanks for all the previous posts because a searched the site for troubleshooting ideas! Jim