No 3rd with C4
 

Only getting first and second gear with the C4 trans. It's not going into drive. When you jack it up it still wants to spin the tires in drive as well as neutral. I'm thinking it's going in between gears D/N, maybe need to adjust the shifter cable. Thought I'd ask here.

I don't have a vacuum line hooked up to that vacuum actuated shift solenoid though, I was thinking it only mattered for automatic shifting and didn't know what would happen if it saw boost.

Any thoughts?

try shifting it on stands using the lever on the trans first

hope it's minor