I have a 2010 ford f150 with a 4 speed 4r75e with around 145k miles on it. Got it basically for free from a buddy’s dad, truck was very neglected, had to replace entire front brake assembly’s, get valve, plugs coils and injectors. Got it running good and strong, noticed the trans cooler lines had busted at the quick disconnect crimps, tried replacing the entire line set, but after trying to undo the flare bolts on the trans for an hour I stopped cause I didn’t want to break something off, so I used tubing cutters and cut off all the rusted and leaking parts and re ran the lines with rubber hose, changed fluid and filter, trans was very low on fluid so that def didn’t help. Drove it just fine for about 2 weeks and checked fluid daily and put paper towels under it to make sure it wasn’t leaking, looks like the front main seal is leaking but not to the point where it’s like pouring out. Had to go on a trip for a few days and the truck didn’t run, got new wheels and tires while I was gone so was super excited to put them on. Got back truck started up strong, threw it in reverse to get it in the driveway with no issue. But once I put it into drive to pull into the drive it hesitated and made a very slight thunk then went into gear. Put wheels and tires on went to test drive and again reverse was good but hesitated and clunked heavily into drive. Thought it was because it was cold out so wanted to drive it to heat up the fluid. Every time I would slow down and it would idle it would thunk into drive and I would have to give it some more rpms than usual. Called it quits and headed home. Got stuck at a red light, when I went to go it didn’t move, tried giving it some more gas, rpms shot up to like 6-7k then BANG. Trans completely blew up, no forward or reverse and it had a bad grinding noise. Has someone pull me up the road to a trans shop and it currently is sitting there. Would anyone have any idea what all could have gone wrong, is this something that could be rebuild or it is toast entirely? Any input would be awesome.