Volvo hybrid excavator

[HerculesLove]

I am in the middle of bag 10 and some gears won’t move which I knew would happen when I put the motor in, but some still move. Is this normal for this stage of the build 

[1980SomethingSpaceGuy]

Sometimes gears are a too tightly assembled and won't move easily enough; backtrack the issue by trying all axles sequentially and loosen them a bit.

It happened to me once that a gearbox was very hard to operate, even after that. I restarted from scratch and the second time worked much better.
Still unsure what caused the issue as there were no building errors...