NHTSA Complaint #11657965 — 2020 CHEVROLET SILVERADO 3500

I recieved a recall notice from Chevrolet stating they needed to install a software update to the truck which will warn if a potential rear wheel lock up is about to occur due to faulty transmission valve body- which was stated that they do not have a fix for. After software update was installed- I was driving about 35 mile per hour on the trip home, and the truck abruptly downshifted very hard, momentarily locking up rear wheels, and the check engine light came on, and the vehicle message came up stating the vehicle was placed in a reduced propulsion mode(limp mode). The next day it did it again on my short drive to work of 2 miles. I took into dealership and they informed me that the valve body had failed- as mentioned in the recall notice. It is now 1 month later and I still do not have my truck back, the part is back ordered, and they have no idea when it will be fixed. I am without my primary form of transportation.