Since we cannot assume the solenoid is functional, until we confirm that, we need to verify the wiring delivering the signal to sol "B" is with no open or poor connection coming from the trans control module.
Was this problem present before you did the work?
Unfortunately, if it was , this is a perfect example of what can happen it parts are thrown at a problem with out actually verifying the root cause.

 

How can I go about checking it

 

This requires a wiring diagram and a multimeter. Do you have access to that ?
As far as confirming the physical operation, that requires the solenoid be removed , energized and checked for actual physical function. Might be cheaper in the long run to buy the part from Ford, check it before installation ,then install it.

 

I have multimeter but can’t find wiring diagram

 

Can you tell me where the Tcm is located on a 06 f150

 

So one day i was driving and when i tried to back up into a parking spot it was like it was in neutral and then caught year and made a clunk noise and then ever since then it made a grinding noise so I jacked it up on the back end and put it into gear and when it was in Drive it made a grinding noise at the transfer case and when I put it in reverse the grinding noise Came From the transmission and then I pulled the transmission pan and found pieces of metal at the bottom so I pulled the valve body and the Servo rings we're still there and cannot find the problem please help???

 

It's been 4 days, don't know if the problem was found and corrected.