I put in reverse and I can feel it hammer in reverse

Yesterday I was slowing down at a stoplight before it turned green, and I tried to give it some gas and it just wrapped and finally you know kind of coasted back in, but I could feel the loss of power dramatically. So, I pulled into a parking lot shut it off you know checked all my clothes they're all good. The OD light did flash. I've tried taking it up to O'Reilly's to get the code read but they keep telling me they can't read it. But whenever I got back in my truck to start it, I put it in reverse to back out of the parking spot and that was acting the same way as drive. I can feel every gear click in except for neutral and drive whenever I cycle through the gears. So, I put in reverse, and I can feel it hammer in reverse I just had the transmission rebuilt just a little over a year ago, but I have to floor it to get it to actually reverse maybe two miles an hour. Drive will click into, but you don't really feel it and I can for that, and it's barely even wants to rock almost like it's just got something holding it. So, I jacked up all my tires spun them to make sure I don't have seized up brakes. The driveshaft looks good and when I had it jacked up, I checked for an open differential I don't have that I'm fairly well with vehicles except for transmissions as like the only thing I never learned so I'm kind of clueless on this. I did reach up on the transmission make sure all the connectors were still connected and everything all that's good. So, after I finally got to back up at a parking spot by 4:00 for a minute I'll try putting in drive you know of course it wouldn't go or I didn't want to strain the engine or transmission too much trying to get it to go. But first and second work perfectly fine like they just catch right in and take right off I could still feel kind of a little hesitation but not much and it's probably just because it's a low gear. So, on my way home I had it in second gear driving home and decide once I got up to a higher speed to try shifting it into drive. So, I let off the gas a little, shift into drive, give it a little bit of gas and I can kind of hear it just rev a little bit and then it just clicks right in drive and drive perfectly fine until I come to a stop or really slow speed. I'm really hoping it's not the transmission as it was just rebuilt a year ago With a shift kit put in, but I understand it could be a possibility. Is there Any test I can do here at home to try and kind of identify the problem without having to take it in and spend hundreds on diagnostics? I've read up on two other possibilities one being the shift solenoid and second one is being stuck between two gears but not really sure where to go from here. I've overhauled engines torn them down done measurements, so I have no doubt that I'm capable of doing it I've just never had a transmission in front me to learn. Any advice is greatly appreciated.