Thanks for the quick reply, but that does not appear to be the problem.
I started with a simple pickp truck, I sucessfully used the subtract function to cut out the bed and front wheel well, when i go to use a similiar shape I used for the front well on the back This happends:
http://i296.photobucket.com/albums/m...truck1copy.jpg
http://i296.photobucket.com/albums/m...893/truck2.jpg
The first is before I subtract, the second is after,I have tried moving and rotating with improvement.