The last time I had my van in the shop, the mechanic told me one of the front wheel hubs was done and had a fair amount of vibration and play to it, and that this was probably one of the reasons my ABS light comes on every now and then. I have notice a shimmy in the front of the van recently at highway speeds, but only when the van is not under load (IE, if i give it gas the shake goes away, but if it is coasting, it is apparent).
How hard is it to change the wheel hub on this vehicle? I'm a average level backyard mechanic (I've done brakes, belts, gas tanks, starters, alternators, water pumps, rads, replaced a head gasket, etc), but don't have much access to specialized equipment.