Grasshopper gearbox issue

[Itsallicanafford]

Any advice much appreciated. A friend has built his son a Grasshopper but has never got the gearbox working correctly. It sounds from his description that the cog on the motor is not engaging correctly with the first cog of the gearbox. He explains that he has had it apart and reassembled it a few times but still not working. Any thoughts would be great so I can pass on.

[shedweller]

Most likely that the brass spacer on the shaft is missing or on the wrong side... Pictured below (circled).... Beyond that there is not much that can be wrong...
Sometimes the shafts hexes can round off but if it hasn't been used it is unlikely to be that

[Itsallicanafford]

thanks very much for taking the time to post, i will pass it on and see if this fixes the problem.

many thanks again, much appreciated.

Cheers

[CubanPete]

On other Tamiya models, there are different positions for the motor to be screwed depending on the pinion tooth count.

Not sure on the grasshopper!

[Gary29]

Loose pinion gear? (Gear mounted to motor shaft) Pinion gear fitted the wrong way round so it doesn't mesh with the spur gear?

Could be a number of things, and would be an easy fix for most of us RC nerds on here, but we would just be guessing, maybe if he could take a few photos and a video if he's really struggling then we would be in a better position to advise.

[C.A.R.]

Grasshopper comes with a 380 motor as standard, with a brass pinion gear which has press-fitting, so unlikely to be a problem with that. Also can't be alignment as I don't believe it's possible to mount it in any other orientation / pinion gear ratio.

Would put money on the brass spacer being missing as it is easily overlooked.

[Itsallicanafford]

Thanks chaps for all the replies, will have a chat with my friend and report back when we have progress! Cheers