We've just finished 9398 4x4 Crawler. Everything looks good, the motors work but the front wheels rotate in the opposite direction to the rear wheels, they also turn in opposite directions. What could be the problem?

1 Answer 1


Likely you'll have the differential gears oriented wrong in the front or back section.

The differential gear is this piece:

Differential gear

Please check the instructions carefully and see if the orientation of this piece in the instruction book matches your build.

  • 1
    You're right! This piece was in a wrong position. Now everything works properly. Thanks a lot!
    – Belle
    Commented Jan 2, 2019 at 14:59
  • 1
    Thank you so much for this post and the responses. I had the same issue with the 42082 crane that was most of the way built, before my son realized that the front and rear axles were turning in opposite directions. After reading your posts and checking the instructions, I began carefully taking the area around the differential apart (there was some slight bending of pieces involved), to flip the front differential piece that was shown in the earlier respondent's photos. Flipping the differential piece fixed the problem and we are back on track.
    – Patrick
    Commented Jul 11, 2020 at 20:39

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