why a tranny works only when the truck is cold temp ?

fluid is thick when cold. when its warm its probably bypassing a seal that it couldnt bypass when it was cold

Does it have enough fluid?

evrything is normalwhen is cold, n fluid is good , may be a bad TCU ? u know like hondas have a bad main relay that as soon they get hot they start acting up

Still think you have a internal issue

it willneed to be replace? how much that would cost me? or an idependient oil cooler would help?

I think it will need to be taken apart and see what you can find. It would be cheaper than replacing it. I dont think a cooler would help. Yes it helps cool alot but i dont think it would keep the fluid cool enough to help it move like when it is cold.

alright thanx