Some insight about (a specific) gears.

At the moment I am building the 42098 set. While building the trailer part of the truck and (think) i have done something wrong. I have build the gear set as seen in picture 2 (seen from above) and 3 (seen from below). But whe i turn the grey socket, i only have a limited range that i can turn (8 to 9 times) the axle before it blocks. And it doesn't seem to block because the pieces who are attached are blocking movement but because the gear just seem to block. The questions i have : For the...