Happy Hoildays ,
I have a question will the 545rfe trans from a 2005 4.7 2wd quad cab be a direct swap into a 2005 quad cab 4x4

 

Nope, won't work, at all. You need a trans out of a 4x4.

 

Internally, functionally, and the main body should be the same transmission.
However, it is definitely not a "direct" swap from 2wd to 4wd. As a minimum, the bolt on tail piece of the transmission needs to be changed. The 2wd is a long output shaft tail piece, to be removed. The 4wd has a short stub spacer piece, to be added, which is flanged to bolt on the transfer case.

 

Is the output shaft on the trans the same though? That's the biggest problem I have seen, but, not on these specific transmissions.

 

I understand them to be exactly the same in all aspects, except for the bolt on tail pieces difference between 2wd/4wd. Meaning if you already have a 4wd transmission, you can buy a 2wd transmission, unbold the tail piece drive off the 2wd unit, unbolt the tail piece spacer off the 4wd unit, bolt the 4wd spacer onto the new transmission, and be good to go. Or buy a transmission with no tail piece at all and make the 4wd spacer swap. Yes, I believe it is that simple, mechanically.
I have no idea If there are any differences in the control or solenoid modules (TCM). It is doubtful, meaning they should also be the same and get there control points from the PCM anyways.

HOWEVER, am by no means an expert of these, I merely dabble alot. Please check with a tech lead at a transmission shop to confirm before spending cash and labour on it. I would have called my guy today, but given the calendar date of this post I would not get a definitive answer until probably Thursday.