[12Ounce]

It's a combination of things, ... but the condensation drip is very important, I believe.

Observations and theory:
1. All axles seem to break in the same location ... where the condensation drip occurs. My 99's rear axle is nowhere close to failing, but I can see where the early drip-errosion has begun. Thus far, the errosion on my axle has not gone thru the paint... but it is precisely where all axles seem to break into.
2. All Windstars with rear ac have a flood of condenstion dripping from the rear unit ... some comes from the cooling coil and is "expected" ... some drips down from exposed refrigerant tubing. Condensation is very pure water ... a very good solvent, especially for salt ... the water and salt would be a powerful rust engine.
3. The problem could have been prevented by better corrosion protection on the axle ... better condensation control ... or a combination of both.

... all my unproven theory.