I need help into assembly

Hello,

I designed and draw a assembly with one motor, 2 gears, etc. The assembly works perfectly, it rotates like it should do.

But then (using pack and go, renaming files) i added in the assembly another assembly (basically the same assembly but from other folder) and now I've lost the ability to move the second assembly (it doesn't move like it should do....if I open this assembly from tree manager it works perfectly but in the big assembly it's not working. Please help.

I've attached a picture:

The red gear turn perfectly fine and rotates the entire assembly as is mated together but i cannot turn the black pinion to turn the yellow gear although if i open the assembly separately it works fine.

Thank you

SolidworksAssemblies