I am having major transmission problems. Truck is 2011 Silverado with 4L65E transmission. Had problems shifting into 2 & 3 for awhile and RPM would just rev up when going up hills. Had transmission rebuilt, got it back few days later and everything was working fine except it shifting really hard from 1st to 2nd. So drove for few days thinking it would work self out. Took it back to shop where the guy flashed the computer. Got it back, drove it 50 miles or so and it started acting like I never even had the transmission rebuilt. Took it back to the shop where the guy replaced the transmission computer. He claimed he drove for day or so and shifting fine. Well got it back and after 2 days it starts having trouble shifting out of 3rd gear. 1st, 2nd, and reverse are all working fine but fastest I can go is 55mph. Drove it back down to the shop where he tells me he has done all he could do and can't fix it. He willingly gave original money back, but now I'm stuck with the truck and no one to fix it. Don't want to get another transmission rebuilt in case it's something electric and not the transmission. Really need some insight or someone else that has had similar issues. I would really appreciate the help!