drain the gearbox and refill with ATF the valves in the gearbox stick due to dirty ATF.
It will until the coolant warms up.
change the gearbox oil it is ATF you have sticking valves due to dirty oil. and oil all linkages.
Wait until it warms up and melts
better look into getting a new cable for it sometimes they get water or rusted inside and makes it difficult to engae till the cable warms
cold start switch on the side of or on top of the throttle body.
Try checking the trans fluid. The level of the fluid drops when the engine becomes hot. Check the fluid with the engine idling with the trans in park.
Often a knock when cold is caused by piston slap, which is pistons rocking in the cylinders until they expand in size when the engine warms up.
replace your mapp sensor
its prob the thermostat i had the same problem with my uncles
this is caused from piston to cyl wall clearance when engine warms up the pistons exspand and the noise is less. DON'T WORRY ABOUT IT
Possible dirty fuel injectors or TPS sensor.
I would check the transmission fluid level.