i have this assembly with the universal joint, as in assembly 1, when i fix these 2 white cylinder and i rotate the grey cross, the system still rotate as it should with weird movement at the big wheel so i decide to fix the white part with 2 holes but after that, the whole system wont rotate anymore, tks if any1 know what is wrong with my mate because i only self-taught solidworks through internet and i want the system still rotate after i fix the white parts. HERE are my 2 pics and the whole part and assembly files. Tks all