The Volvo 8700 mod often comes with multiple .bus files. Rename or select:

To change the gearbox permanently, edit the .bus file with Notepad. Look for the line [gearbox] and change the file path.

By default: C:\Program Files (x86)\Steam\steamapps\common\OMSI 2

Run OMSI 2 > Bus Selection > Volvo 8700. If the bus appears with textures, you are 90% there. If it is invisible, your Vehicles folder structure is wrong.

The Volvo 8700 can be FPS-heavy due to high-poly interior. To make it work smoothly:

Even after installation, you might encounter issues. Here is a diagnostic chart for OMSI 2 Volvo 8700 work problems.