Need help on diagnosing a problem with my 4L80E transmission on my 2000 Silverado w/ 6.0. Transmission is going into a sort of ‘limp mode’ when towing or if transmission heats up starts shifting HARD into gear, I mean it slams from gear to gear when shifting. This problem has only happened to me about 3-4 times, last time being about 2 months ago when I was towing a friends truck on a car dolly from Columbus, OH to Lansing, MI (about 250 miles). I hooked up a snap-on scanner to my truck computer and it did not pull any codes or show any problems. I was thinking about bringing it in to have a tech II hooked to it to see if that would read anything. Usually the transmission will heal itself after I shut the truck off and re-start it-- it eventually goes back to shifting normal. I am clueless to what the problem is, fluid looks good—I just did a fluid & filter change about 10k miles ago. I don’t know if this is like a TCC solenoid or internal problem or what. Anybody have any ideas or suggestions on what to do or check at this point? Help