2001 Chevy Tahoe will not go in to gear

To my knowledge the vehicle has never had any transmission problems. I had it checked out by a chevy dealership and they did their 27 point inspection a couple months back and no stand out issues. That being said, I've never had a difficult time getting it to go in to gear but sometimes when starting out, it shifting to the first gear was rough. Also, even though rare, every now and then I'd drive and it seem like it was slow to shift and I was accerlaring but it never switch gears until I backed off and let it catch up if that makes sense.

Today I was driving on the interstate and towards the end of my drive something felt funny like it wasnt in the right gear. I got off on my exit and pulled to the shoulder and put it in park and revved my engine. I just had my fuel pump replaced recently so worried that was the issue. I went to put it back in gear and I can go through all the gears with the gear changer but it's like it never clicked. Couldn't go in reverse, drive, or any of the lower gears. This is an automatic transmission by the way. When putting it in to gear it was like it wouldn't catch. Starts fine, I can use the changer fine and cycle through everything but it just doesn't catch for me to go.

I had it towed, dreading to find out how much the problem might cost so trying to prepare myself for possible issues from you guys.