Neutral to reverse slams and knocking

[swathdiver]

02 Yukon 4wd 5.3/4l60e.
Recently had transmission rebuilt had done issues with the guy that did it and had to take it back to him twice now. Anyway, the day i got it back all forward gears shift fine and going from park to any gear does fine. When going from neutral to reverse it delays going into gear and when it does engage you can hear 3 or 4 knocks then just slams in jerking the truck. Hopefully the video will load. The guy who rebuilt says everything is new and claims its the transfer case, another guy just quick diagnosis says it seems like a solenoid pack. And reading stuff on here sounds like it could be any of those plus tps, maf, pcm or number of things. Any help would be appreciated thanks.

Get hold of the shop manual and run through the troubleshooting guide. If you idle is low, what is the commanded and actual RPMs, do they coincide? Same with the PC Solenoid Current for starters.