Anyone with ICS split gearbox design tech knowledge, help

[SCAR_Jester]

So I'm trying to put in some new gears to my ICS CXP 16 L, however when I get to the "switch to semi and pull gearbox out" part, it comes out half way then gets stuck. Am I missing something because I have no idea what is going on and there is no visual sign of something stopping it from budging.

(and yes all other steps have been checked twice)

Any help is greatly appreciated

Thanks

- Corky