Looking at my uncle's 2004 Sierra 1500 Z71 with a slipping issue. Once the transmission fluid warms up going about 55 or so and going up a hill the RPM's will skyrocket and if you try and hit the throttle it doesn't want to go any faster. I hooked up my scanner to watch the data pids and the TCC slip rpm counter goes up above 2000 rpms while the PCS values drop when it happens. The truck had a new transmission put in a couple years ago and the fluid/filter have been changed once with around 25000 miles. I'm kinda leaning toward either torque converter or computer issue, thoughts? (The PCM got submerged in water in a bad storm a few years back and he did have some electrical issues with the fans but that has since been resolved)

 

can't see the data. if the tcc is locked up and its showing a high slip rate....and a engine flare....check the fluid...does it smell burnt or is it brownish? Does it slip in all gears; manually shift to low, 2 and drive or just one gear? If you have dtc...post them.

if it only slip in one gear...the fault is probably a holding member not the tcc. drop pan and inspect.

 

it mainly slips in overdrive when going uphill (more load), but occasionally has a surge between second and third. The fluid was overfilled by 1/2 a quart but we adjusted the level and it still slipped. The fluid was recently replaced and doesn't smell burnt and looks red. No dtcs are being set except for a b1s1 02 sensor