My 2009 Suburban has transmission issues it's a 6l80 it started off by not moving after a stop i reved it and it went along at a slow pace it stopped at a small grade i revved it again a managed to limp to where i was headed i dropped the pan and the fluid was black and smelly. so i went ahead and replaced the the filter and refilled with delco dexron vi and everything seemed back to normal except for an occasional rough shift to 1st gear and delayed reverse so i pumped out 16 ounces of fluid and added seafoam trans tune in hopes of clearing up the shift issue. drove it a week and suddenly i lost drive except for M1 and no reverse. So i did a transfusion fluid change used four gallons to get to red fluid no help. I hooked up my clone tech 2 and got an 842 code low transmission fluid pressure viewing the data my line pressure is 13psi in all gears except M1 which is 58-60 also when i select the valves through the tech 2 it shows the pressure at the valve is 565 lbs per the tech 2
