This is a semi truck toy with a tank trailer.It is almost the same as https://www.cgtrader.com/3d-print-models/games-toys/toys/semi-truck-toy-fully-3d-printable-assembly-experiencebut with the semi truck havind two rear axles. So the assembly process is more orless the same as for that one.

For the tank trailer print as many middle modules as you wantto get the tank length that you want.

The tolerance for pieces that need to fit tightly is 0.1mm,for pieces that need to allow movement (like screws and axles) 0.3mm or more.

Printing list: Nb. STL file name rezolution support colour (my make)

• 1x articulation_plate.stl 0.16mm no red
• 1x articulation_screw_semi_truck.stl 0.16mm no gray
• 4x axle_back.stl 0.16mm no gray
• 1x axle_front.stl 0.16mm no gray
• 1x backhead_semitruck.stl 0.12mm no black-white
  
• 1x backhead_trailer.stl 0.12mm no black-white
• 0x back_light.stl 0.16mm no
• 4x back_light_with_flat_cut.stl 0.16mm no orange
  
• 3x back_light_with_flat_cut.stl 0.16mm no red
  
• 1x back_light_with_flat_cut.stl 0.16mm no white
  
• 2x base_dist.stl 0.16mm no orange
  
• 1x base_truck_left.stl 0.16mm no gray
• 1x base_truck_right.stl 0.16mm no gray
  
• 1x base_trailer_left.stl 0.16mm no gray
  
• 1x base_trailer_right.stl 0.16mm no gray
• 1x cabin_cap.stl 0.16mm no blue
  
• 0x cabin_with_support.stl 0.16mm no
  
• 0x cabin_your_own_support.stl 0.16mm yes
  
• 1x cabin_spare_wheel_hole_w_support.stl 0.16mm no orange
• 4x cap_double_rim.stl 0.16mm no gray
• 4x cap_double_rim.stl 0.16mm no black
• 2x cap_double_rim.stl 0.16mm no orange
  
• 2x cap_single_rim.stl 0.16mm no orange
• 3x connector_base_tank.stl 0.16mm no orange
  
• 1x exhaust.stl 0.16mm no black
• 1x front_grill.stl 0.12mm no black-white-black
• 1x front_lights.stl 0.12mm no orange-white
• 1x interieur.stl 0.16mm no gray
  
• 1x interieur_base.stl 0.16mm no red
  
• 1x mirrors 0.12mm no black(TPU)
  
• 8x rim_double.stl 0.16mm no white
  
• 4x rim_single.stl 0.16mm no white
  
• 2x roof_light.stl 0.16mm no orange
  
• 1x screw_gear_knob.stl 0.16mm no black
  
• 34x screw_l6mm.stl 0.16mm no blue
  
• 15x screw_l9mm.stl 0.16mm no black
• 10x screw_l13mm.stl 0.16mm no orange
• 1x screw_for_spare_wheel_on_cabin.stl 0.16mm no orange
• 0x sleeping_screw_l9mm.stl 0.16mm no
  
• 0x sleeping_screw_l13mm.stl 0.16mm no
  
• 1x spare_wheel_holder.stl 0.16mm no orange
• 1x steering_wheel.stl 0.16mm no black
• 2x tank_cap.stl 0.16mm no orange
  
• 1x tank_end_module_nocap_noladder.stl 0.16mm no white-blue-white
  
• 1x tank_end_module_nocap_w_ladder.stl 0.16mm no white-blue-white
  
• 0x tank_end_module_w_cap_noladder.stl 0.16mm no
• 0x tank_module45mm_art_nocap.stl 0.16mm no
• 1x tank_module45mm_art_w_cap.stl 0.16mm no white-blue-white
• 2x tank_module45mm_nocap.stl 0.16mm no white-blue-white
  
• 2x tank_module45mm_w_cap.stl 0.16mm no white-blue-white
• 14x tank_screw_pad.stl 0.16mm no blue
• 12x tire_outter_cut.stl 0.16mm no black(TPU)
  
• 8x tire_simple.stl 0.16mm no black(TPU)
  
• 1x tool_box_left.stl 0.16mm no blue
  
• 1x tool_box_right.stl 0.16mm no blue
• 1x wheel_house_back_left.stl 0.16mm no black
  
• 1x wheel_house_back_right.stl 0.16mm no black
  
• 1x wheel_house_back_left.stl 0.16mm no gray
  
• 1x wheel_house_back_right.stl 0.16mm no gray
  
• 1x wheel_house_front_left.stl 0.16mm no black
  
• 1x wheel_house_front_right.stl 0.16mm no black

Observations:

• all objects already have the intended print direction in the STL files!
• if you don't like the built in supports for the cabin,then you can find only the cabin in cabin_your_own_support.stl
• most of the parts were printed with PLA. only the tires andthe mirrors were printed from TPU (flexible material)
• screws... there are also sleeping screws STLs includedthese are printed on the side which makes them a lot strongerthe drawback is that these don't close the holes completely...So use as many sleeping screws as you can if the toy is going to be played with, and only normal/round ones otherwise