Chevrolet Repair: transmission, sway bar linkage, tie rod ends

Question
Just had my 1999 Chevrolet blazer at a mechanics shop with repairs to the transfer case output seal, lower control arm, lower ball joint, sway bar linkage, valve cover gaskets, transmission filter and gasket, left front axle, outer and inner tie rod ends, and now the vehicle does not shift gears(automatic transmission) while driving. Can you tell me why this is happening to me after repairs to these components?

Answer
GOOD DAY CHRISTOPHER, I THINK I HAVE A GOOD IDEA WHAT IS GOING ON HERE. IF THE CK ENGINE LIGHT IS NOT ON IT WILL BE SOON. I THINK WHEN HE PUT THE TRANSFER CASE TAIL BACK ON  HE DID NOT HOOK UP THE SPEED SENSOR OR HE DAMAGED IT. THIS IS WHAT TELLS THE PCM [COMPUTER] HOW FAST THE TRUCK IS MOVING TO TELL THE TRANSMISSION WHEN TO SHIFT AND AT WHAT SPEEDS..DOES YOUR SPEEDO WORK ????
IF NOT, GO UNDER YOUR TRUCK AND LOOK AND THE BACK SIDE OF THE TRANSFER CASE AND SEE IF THERE IS A WIRE HANGING LOOSE.FIND THE SENSOR AND PUT THE WIRE BACK INTO THE PLUG AND ALL THINGS WILL BE GOOD AGAIN..I HOPE THIS HELPS  YOU AND IF NOT GET BACK TO ME..GOOD LUCK TO YOU,,TOM