As you can see this is the original truck with 2 axle that Giants disponibilized on it's website.
Since is a little look alike, I put a Freightliner logo on the truck's front, and one on each mudflat.

Also I added 6 types of engines:
Cummins X10 V6 (400hp)
Cummins X11 V6 (440hp)
Cummins X12 V6 (480hp)
Cummins X13 V8 (520hp)
Cummins X14 V8 (560hp)
Cummins X15 V8 (600hp)

Credits:
Giants, Christian Ohlweiler