Hey guys, I'm looking to swap in a 4l65, 4l70, or 4l80 in place of the 4l60 that failed me at 170k miles. I have a 2004 Silverado 1500 4x4 crew cab with the 5.3. I like the price/ warranty of this 4l80 here, https://reman-transmission.com/trans...s/?code=4L80-E, but they can't confirm it will fit without modifications. Can anyone here confirm and also tell me if it will make that much difference coming from a 4l60 with regards to towing and longevity?