Volvo Racing truck gear problem

[Chugster2204]

So i just downloaded a mod with a Volvo and Mercedes racing truck, now the Merc is fine but when i drive the Volvo the gears dont shift automatically, even with auto-shifter on.

Is this something I can fix or is it down to the mod maker?

 

[Chugster2204]

Ok so I have found a few other mods with this same issue...is there anything I can do to fix this?