Shouldn't take more than 2 hours, take lots of pictures if its your first time, memory is a tricky thing, lol, especially if you are interrupted by something else.
I would flush the cooling system first, if rad was leaking from a rust out then other parts of the cooling system will have been effected.
This will add to the time since engine needs to be heated up for flushing fluid to reach all the parts, remember to turn Heat on to Full, blower fan can be left on off.
Also feel the heater hoses in the engine compartment, the hotter one is the IN hose, cooler is the OUT hose, label one for later use
Disconnect battery
Remove rad cap and overflow hose, put overflow hose lower than overflow tank, that should drain the tank, rinse tank out with water, and make sure it comes out clean, no debris.
Start draining coolant from rad
Remove air plenum from intake, both ends.
Unbolt and move fan shroud back and out of the way, as much as possible, lol.
Remove upper rad hose
Remove lower rad hose, from engine end as well
Have a couple of small containers ready, and rubber bands with sandwich bags
Unbolt the trans cooler lines at the bottom of the rad, trans fluid will leak out from rad and the lines, put sandwich bag over each line, twist it tight and hold in place with rubber band, just a gravity leak so no pressure.
Containers are for trans fluid leaking out of rad.
Unbolt rad from rad support
Remove rad and lay it flat to stop trans fluid from leaking.
Get new rad and compare trans cooler hook ups, sometimes you will need to remove insert/adapter from old rad trans cooler to use in new rad.
Install and bolt new rad to rad support
Hookup trans cooler lines
With coolant drained I would take the time to back flush the heater core at this time.
It is simple and well worth the effort, remove heater hoses from engine end.
From above check of hot and not as hot hose check
Take the IN hose and bend it so it points down at the ground
Take a garden hose and hold it tightly against the OUT hose end
Turn on garden hose, lower pressure is fine
This will push any larger debris in the core out the way it came in
If flow thru core is slow you can use a mixture of warm water and CLR or Vinegar.
Blow out the water in the core, just your lungs are fine.
Fill core with mixture and let it sit for 20 minutes
Then use garden hose again and see if flow has improved
Repeat as you see fit.
Reinstall heater hoses.
Reinstall lower rad hose and upper rad hose
Reinstall fan shroud.
At this time I would recommend starting engine and checking trans cooler connections.
It is ok to run a cold engine for a minute or two without coolant.
It will only take trans pump a few seconds to build up pressure in those lines so you will know if connections are good within 1 minute.
If all is well, remove 1 heater hose from firewall and lift it up so it's the highest point on cooling system.
Refill system with coolant
When coolant starts coming out the heater core, lower heater hose and reconnect.
That should prevent an air lock when first starting engine.
Fill rad the rest of the way.
Hook up overflow hose
Fill overflow tank to Cold Mark.
Start engine with rad cap off, coolant level should drop a bit top it off, when level seems stable put on rad cap.
Go for a drive to get engine up to operating temp, this should purge the rest of the air in the system via the overflow.
Check trans fluid level(warmed up is best) and top up as needed.
Let engine cool off then check the overflow tank level, top up to Cold Mark if needed
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