2008 5.3 175k - forward in reverse and neutral after repositioning in yard

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Hey guys, new to me truck, 175k.  Had truck shipped to me from GA, knew it had some issues.  Backed it off the trailer.  Drove it up to advance and had the codes read.  P0641 (5v reference) along with crank position sensor code, Oil pressure sensor code, fuel tank code, two tpms sensors, airbag fault, and occasional stabilitrak fault.   Sat in the yard a couple days while I cleaned the interior (smelled too bad to really drive it).  Looked up the 0641 code and realized I probably had a wired rubbed through so decided to move to where I could get under it and inspect.  Charged the battery overnight.  Got in it, backed up up, pulled it forward round the yard and it tried to get stuck.  Shifted it in to 4wd and it did not want to move.  Shifted it back in to 2wd and finally got it back up on the pavement.  It spun a little in the grass before the gov lock kicked in and got it up on the pavement.  Tried to back up and now it goes forward in rev and neutral.  I would not think that little bit of drivng would have welded the clutches but have not seen any other explanation?  What should I start with checking?

 

BTW, pretty expert mechanic but it has been a few years since I had a Chevy truck, my last one was an 88 4x4.

 

Any recommendations appreciated.