Welcome to the forum and irv2.
Here is
a link with important info related to Newmars and links to see the inner workings of a Newmar.--
Brochure --
Owners Guide.
The
NEWMAR CORP link has construction video's of chassis and wall construction and many other items. --
WALL CONSTRUCTION
When a new gas chassis comes into Newmar the chassis rails have a arch to the surface as you see when looking at a empty truck trailer bed, when it leaves the chassis shop the rails are completely flat ready for the build on the Newmar model ordered, the under structure is well reinforced to support the coach body.
All coach's gas or diesel are built on same floor by the same builders of gas or diesel.
All links in my signature have answers for gas or diesel problems in your Newmar.
Enjoy the forum and good luck in your per suite of what ever coach you get.