I can't get both tail pipe pieces to fit over the rear axle there isn't enough room

 

How big is your spare tire? Mine was 5" single and I barely had enough room to come over the axle and around the spare, but yours being 4" should clear.

If the spare is anything bigger than stock though it may be too big. I'd start with the pipe that goes over the axle and build forward once you get it in place. It's a bear to wrestle in.

 

I took off the tire and the bracket and both of the 4 in won't fit only one will

 

you know we are trying to picture in our heads.....Did you jack the truck body up and let the suspension hang creating a larger space to put it over the axle? Not sure that is your problem when you say it won' fit but I would say that is not the issue then you will have to call them. Keep trying....

 

In the instructions it says to put the y pipe in vertical and the two pipes won't fit on top of each other. I'll try to put a pic on when I get off of work