All, I have a 2001 Yukon XL with 4I60E transmission. I did a complete transmission flush about 5k miles ago and the truck has been doing great. The only issue was an oil leak from the pan. I finally decided to go at the leak and lowered the pan. I couldn't get the pan completely off, but was able to unbolt shift linkage, and move pan enough to replace the gasket. I reassembled everything, but now the truck won't go in reverse, and when in drive it has a hard time shifting into second. What did I do? It was working well before and immediate after, it's not. I'm wondering if something got damaged when I was moving the pan back and forth trying to get it off. Shift linkage looks good. Anyone have any suggestions on what I should look at? Some online videos suggest checking fuses, but all of the Ignition 10A fuses look good. Also of note, I did replace some of the transmission fluid again.