Was driving down the highway pulling a little 4 wheeler trailer, blew a trailer tire, had to run about 2 miles down the shoulder to get off the freeway. Got both trailer tires replaced, got in the truck and got back on the highway and now I only have 1st and second, trans fluid is nice bright red, truck only has 90k miles. What is going on? Even manually shifting I can't get to third.

 

99 tahoe auto trans 123D. With 258,000 miles. Driving 70mph cruise control on then Loud bang then nothing in 2wd all gears not working. Put in 4wd high nothing all gears. Tried 4wd low and 1&2 driveable but nothing in 3&D. And reverse works in 2wd, 4wd high,and 4wd low. What the heck is up? Tranny fluid is brite red and full. I need some expert advice can anyone explain this it's not not making any sense. ???