Neil,

Sitting outside would not lead to undercarriage corrosion unless the area unless the roads are salted.  I've had no rust or corrosion on my never garaged VW vans in the rainy northwest for over 40 years.  And, long grass won't grow under them, any grass parked over will die without water and sunlight. 

Your van has spent a lot of time in the "salt belt."

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Neil N

On my '88 Westy, transmission case material at the shift linkage bushing mount point . . . As a side note, given the areas of rust I see at underside, and this case corrosion, I have to wonder if this bus sat unused for some time in a wet field with long grass or similar.