It's a simple trick that makes the tread texture move along the mesh, simulating tread movment.
As you are applying the texture in RenX, in the material editor under Pass 1, Vertex Material tabs, you have the Stage 0 Mapping section. There, drop the box down aside Type: and select Linear Offset. In the box immediatly below, type in:
Then continue to apply your material as normal and line it up with UVW Mapping. It wont be moving in gMax.
Export to game, and take a close look. If the tread is moving sideways, replace the V in the code with a U or W. If the tread is moving backwards, place in negative 1 after the equals sign. If the tread isn't moving, start again and type it right, it is case sensitive. If that fails it's a mesh name/ini problem, but in my experience getting the treads moving is rarly the problem. Getting them to stop is a problem which sparks up much more often.