I have fix your problem
it took't time but i fixed it, almost as you wannn it.
when you drop the units (ghouls) then you never can enter the Transport with units again, so it works 1 time then you need to buy a new unit.
:Object editor:
Change meatwagon abilities
delete desise cloud from meat wagon
and add mana initial amount 8000 and mana max 8000 and 0.00 mana regenation
:Abilities:
Exhume corpse; mana cost 1000
Duration; 0.10
Maximum number; 1
Techtree - requirement; none
:Trigger:
:Event:
Unit - A unit Starts the effect of an ability
:Condition:
(Ability being cast) Equal to Drop Corpse
:Action:
Unit - Create 8 Ghoul for (Owner of (Casting unit)) at Position of casting unit
Wait 0.10 seconds
If (all Conditions are True) then do (Then Actions) else do (Else Action)
If - Condition:
(Unit-type of (Casting unit)) Equal to Meat Wagon
Then - Action:
Unit -Remove (Ability being cast) from (Casting unit)
Else - Action:
None
//Abe; this works perfect test it and do exactly as i have shown here!!! :lol: