I have a 2007 Yukon denali AWD when i shift from park into drive and i accelerate the truck feel like the emergency brake is on but on reverse its fine everything was working fine when i got home 2hr later when i tried to leave its when it happened no code's please help
Get her up in the air and pulls the wheels and inspect the brakes. You may need a puller to remove the rear rotors as they also contain the parking brake shoes. Join AllDataDIY so you have access to the shop manual and will know how to adjust the parking brake actuator and shoes if necessary. Make sure the pads move freely on the slides and that the pistons are working properly.
I did the front brakes, everything but the calipers as they were working fine and then a year later one piston hung up one day. Fixed it and everything was fine for another few months and then one day it got stuck and took out the pads and rotor. Had to replace everything again and just for good measure I rebuilt the rear calipers too and then used 6 quarts of brake fluid to get all the old stuff out and bleed the brakes properly.
If you are going to DIY and self-diagnose this truck, you absolutely need a Tech-2 or equivalent, not a code reader, but the same tool the dealership uses to work on these things. It quickly pays for itself and is the most important tool in your toolbox.
As for the transmission, most of the time, the first sign of trouble with the 6L80 is that the solenoids need rebuilding which you can do on your kitchen table for about $100 plus fluids. This generally occurs at around 160K miles. Same for the oil pump pick up tube o-ring.