I have a 2006 Chevy Tahoe 4WD. My problem began last night while driving approx 45-50mph my transmission seemed to slip twice. No loud noises, and it only occured the 2 times. Today, I get in and try to back out of my parking spot and I suddenly have no reverse. It operates without issue in drive and I dont appear to have lost any other gears. I have seen a ton of material on issues similar to this so far but cant find any consistancy with what the actual problem is. The tahoe tripped 80,000 miles 2 days ago and I have had no major issues until now. I plan on getting it into a shop tomorrow or the next day but I would like to know what im in store for. HELP!!!