1993 gmc sierra c1500 radiator hose broken - 1993 GMC Sierra

You have the electronic version of the 4L60, so if it was doing it before with your old tranny. I'm going to point the finger at the computer. Probably nothing wrong with your old unit.
If you didn't replace this, then maybe you should.
https://www.carparts.com/details/GMC/C1500/AC_Delco/Automatic_Transmission_Wiring_Harness/1993/Sierra/8_Cyl_5-dot-0L/AC24241212.html

Biggest problem is getting the rotten fitting out of the intake manifold

plastic distributor ? wrong screws in rotor? timing?

the upper hose goes from the radiator to the thermostat hosing. The lower hose goes from the radiator to the water pump.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

automatic transmission models have two lines going direct to the trans

common problem with GM trucks befor 96, is the shifter on the colum?...if so that is what is keeping it fron turning off all the way, if its not in park you cant have the key. hope this helps

Your thermostat may need to be replaced and your water pump may be weak and need to be replaced also. Try replacing the thermostat and flushing out the coolant system and replacing it with new antifreeze. Also inspect the radiator hose, check for the condition there in, if there too soft and when they get hot, the hose may collapse and restrict the flow of antifreeze though the system. After that has been done and you are still over heating, the water pump could be weak and needs to be replaced. Recap: service the cooling system with new 50/50 mix antifreeze, replace the thermostat and replace any coolant hose that is soft. Good luck and hope this helps, keep me posted, be glad to help.

the intake manifold gaskets are leaking. its a common problem on GM's.

its not a hard repair but it is time consuming.

could be a vaccum leak, any work prior to the incident, or just really old hoses could be a problem, i change my vaccum hoses every 2 years

check and see if the heater valve is opening. it should be on one of the heater hoses. If it is open make sure that all the air is out of the engine. check and see if both sides of the radiator are the same temp. They should both be the same. If it was working before you changed the stat, then it could be a bad stat