I've never even owned a GreenLight casting but if the wheels are pressed on like some other better Diecast then you've really got your work cut out for you in trying to remove them without disassembling the car.
You can probably pry one wheel loose with a very small screwdriver,
Then you face the task of having to hold the naked end of the axle with small needle nosed pliers while trying to pry off the remaining wheel.
Trouble is once a wheel is pulled off it's axle it doesn't always go back on 100% straight or securely attached.
--CadillacPat the UnCustomizer--
Keeping the ZING in CustomiZING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
If the wheels clear the wheel openings, yur all set. Otherwize, yank the base....no big woop.
Once axle is out with one wheel remaining, place axle in a vise and EVENLY pry with two small screw drivers. (Do the same with the initial wheel removal from car....EVENLY!!!)
These usually do come off very hard!!! But the end result is way worth it.
If wheel doesn't go on all the way, just file down some of the knurling on the end of the axle.
If you file down too much, just gloo the sumbitch back on!
Important note; don't pry on the outer edge of the rim, you'll tear it up, sure as shootin'.
Pry on the inner most hub area of the rim.
I have found that GL's have some of the toughest wheels to remove. Like Lummox said don't pry off by the rim. They're axles are heavily knurled and you can easily pull (break) the wheel right off its axle hub leaving you a useless wheel. I always remove the base from the car and then I use a speacial pair of pliers that I had gotten from my dad back from his days at IBM. The pliers are speacialy notched and fit right at the base of the axle hub. Once the axle is mounted in a vise all I do is pull the pliers towards me and off comes the wheel. But still I am surprised at times the amount of force I have to exert to remove the wheel.