[vanilla-thunder]

I'm installing a shower in my basement but I want to make sure it was ok to tie into the same drain the sink is on. The drain the sink is on is also a wet vent for the toilet and sink, I read that If the shower is less than 5or6 feet away you can share the vent, correct!? It won't let me upload a pic right now I'll try from my pc later to help with explanation

 

[Windows on Wash]

Probably better to post this in the plumbing section as well as dimensions on the current drain pipes sizes.

 

[Bobplumb]

You can but it has to be symmetrically connected to the toilet and that means that you need to have a junction where your bathroom groups meet so ie a 3"x2" double wye fitting