transmission input speed sensor problem

[richard wysong]

04 2500hd Silverado, WT 6.0, 4l80e, started shifting hard a few months ago, code for input turbine speed sensor, replaced it with a Dorman sensor, at first it was throwing an intermittent signal then nothing, put a Delco sensor in , no change. no sign of damage to the wires or connector, doing the wiggle test while watching live data shows 0 rpm. driving this am it started shifting normal for a while then back to hard shift. I suspect it's either a wiring issue or possible a bad connection at the PCM. My question is, is there anything inside the trans that could cause the sensor not to pick up a signal? Anyone have a pin-out of the PCM? TIA

[davester]

charm.li has wiring diagrams for your truck.  It's been forevee since I rebuilt the 4l80e for my '04, but I believe both the input and the output sensors (for 2wd) are bolted from the outside of the transmission, so the only internal to the transmission problem is really if the tone wheels have debris on them or somehow got broken.

[richard wysong]

Thanks Davester, Highly unlikely there's any internal damage, even though it has 300k miles on it  it runs perfect when the signal is there. Yes both sensors are external end identical