Just did a tranny fluid and filter change on my 04 Colorado Z71. It's got 125K miles on it and a tranny cooler. Followed the Haynes manual and added 3 qts (mix of LucasOil Sure Shift, Fluid Conditioner, and Stop Slip) after buttoning everything back up, and then ran it, parked, for about 15 minutes. Went through each gear, and held a constant 1500 RPMs, without revving, just as the manual advises. Checked the fluid level and the stick indicated I was good. When I took it out for a test drive last night, I had little power, shift points were all over the place, engine was working too hard (3000 rpms in 4th/OD), and everything was getting very hot. When I got it home, I checked for leaks, and checked the fluid level again. Still full, but now the fluid was starting to turn brown. I'm thinking that the filter slipped, and I'm subsequently burning fluid. Does this sound right?