is yours a 89 model i have found that the 89 models have washers (if that's what there called) on the rims most of the time there the s-pac's, well I have only ever seen them on s-pac's
I know this sounds really goofy, but try putting a heat gun to the wheel. The usual reason why a wheel sticks to an axle is because of dirt and corrosion in the centre of the axle, which in a sense works like a locating dowel. The theory is that if the wheel expands a little, it might be just enough to get it free.
Heat up the wheel centre, being careful not to warm up the axle with it. In theory, it should loosen. Heat expands it, which will in theory loosen the shale and corrosion "locking" it on. Would use a heat gun instead of something like an oxy torch unless you consider these wheels expendable