I agree with xqby and ewie: Neither "crave" nor "ache for" work well in this sentence. Perhaps the word you want is "yearn."
The kid is yearning for a toy truck.
This works as long as the poor kid is unlikely to get such a toy. To say that a child "yearns for" a toy strongly suggests that he is in some kind of state of deprivation.
If the truck-craving child was just an example, and you were asking if "crave" and "ache for" mean the same thing, the answer is no, not really. XQBY explains craving well. If it's not for food, it's probably for something else exciting and fun, like drink or sex. "Ache for," on the other hand, contains an element of melancholy or longing; it is similar in meaning to "yearn for."
Both contain a sense of need, but "crave" most often implies an exciting, fun or dangerous need, whereas "ache for" implies a sad, nostalgic, perhaps painful (ache = pain) need.
Though I agree with my fellow forum members that this use is a little dramatic, I'd certainly understand it and might well use something like "to ache for" or "to crave" if I were describing some childs obsession with a toy. As others have suggested, you have a lot of options here for the verb you choose: hunger for, long for, pine for, crave, etc. I suppose any good thesaurus could give you several more. Once again, be advised that these verbs will give your statement a strong, dramatic flavor.
As Owlman and the others have stated, there are many other options to choose from.
ache/crave/pica do not work well with toy trucks.
Pica is an unnatural craving for certain foods. Example: a pregnant woman wanting to eat lots of salt or dirt. Pica is usually a result of a deficiency of certain minerals, or combination of nutrients which result in the craving. As mentioned before, it could apply to toy wooden trucks, but only because it's made of wood, not because it's shaped like a truck. And, the craving would be to eat the wood, not play with the truck.
This is a common way of expressing the strong desire of a child:
The kid really wanted a toy truck for Christmas, but he'd been a bad little boy!