Is this my transmission or my timing?
About a year ago, my kids and I were on a road trip from california to missouri. When I got through SLC, Utah the truck rpms shot up to around 5000 and the temperature gauge was showing hot. I quickly got off the road at my first opportunity to check it out. This is going uphill, btw. When I couldn't find anything, I gave the key a few turns to see if I could pull up any codes, nothing. I basically nursed the truck the rest of the way without getting on the throttle for fear of messing something up. Ever since that incident, it's been sluggish getting up to speed, feeling like it's not shifting when it should and causing it to hit around 3000 rpms just to get up to highway speeds (65 mph here) but even then, it's only wanting to level out around 55-60. Took it to a transmission place, they couldnt pull up any codes. They say “its driving and shifting” fine. I disagree. Today, I had to push it to 4000 rpms just so I could get up to 55 and merge before the lane ended. And after that, it didnt want to go below 2000 rpms. It usually settles on 18-1900 rpms at 65-70 mph. This is a 2001 4.7 4×4. Can someone please help me narrow down the issues I'm having here?