I am trying to solve practive problem 4.6 which asks to find Io using source transformation principle as can be seen in the screenshot down below.

What I tried to do was using source transformation principle to greatly simplify the circuit and then apply nodal analysis to get two constraint equations and find the voltage. Using that voltage V2 and subtract voltage 35/4 gets me the net voltage. I find the current flowing through that resistor 35/12 and calculate the amount of current flowing through the 7 ohm resistor since it is parallel with the 1 + 4 ohm resistors. My calculations can be seen below.

However, when I solve I find that Io is equal to approximately 3.97A which does not match the book which says it is 1.78A. Could anyone point me on my mistake since I am stuck for quite a while and can't seem to find it.