I have a 2007 Chevy Suburban Z71 I lost the high gears in my transmission other than that the truck was running fine I took the truck to the transmission shop and had a new transmission put in it when I got the truck back it said low oil pressure shut engine off the transmission people are acting like they don't know what to do

 

check the oil pressure sending unit and filter screen. Someone just did a write up of it today.

 

That is on the transmission place right
I gave them my truck and it ran fine. They put new trans and now won't run. They need to fix it right

 

thank u
I'll post what happens later