My car is starting fine and then drives great for about 15 -30 minutes or so Then it goes out of gear I guess because it won’t drive? I step on the gas and it just revs. What could this be? I changed the solenoids.
This is a classic sign that your transmission fluid is low, or the condition of the fluid is poor. Unfortunately GM, in their infinite wisdom, didn't put a transmission fluid dipstick in so you can't check this. The only way to check the fluid or fill it is to get under the car with a torx driver. If you have the tools, space and motivation it doesn't look that hard to do, if not then you'll have to take it to a mechanic.
If it's low I'd be thinking why. Fluid doesn't just disappear, if its low then there's a leak, if it's slow you may be able to live with it but if it's bad then it needs attention before you ruin your transmission. If the fluid level is okay but the fluid itself is bad (probably black and horrible looking) then the fluid needs changing. If it's never been changed then it's probably overdue.