3ds Max :: Incorrect Material Render With Attached Polygons

I have a problem with materials not evenly displaying across modified polygons.
 
I started with the dynamic object SPRING, duplicated it then converted both to editable polys. I attached the second poly to the first and bridge two ends to create a continuous spring (there is a reason in another project rather than just changing the height of the 1st spring).
 
When I apply a material, in this case a standard material that has the diffuse mapped to a bitmap that is a colour spectrum, I find that instead of having one continuous colour gradient from top to bottom, the spring has 3 definate areas that it applies the gradient to. The 3rd bridged area which itself is only a few polys, has the entire spectrum applied just to it.
 
I basically want a single change of colour from top to bottom that matches the material.
 
I'm thinking there are hidden settings when you attach polys together, that doesnt reset the overall mapping.
 
Below is a snapshot of the problem, where you can clearly see the gradient that applies itself through the top spring, bottom spring, and differently again in the bridged section. I couldn't provide the working file (.max), as the site doesn't allow this upload.