I came across a couple of kick 3rd members in a junk yard can you tell if they have a locker in them just by looking at them, if so what am I looking for?   I have a local guy with a post n CL that is selling one with a Detroit EZ locker in it, & it looks just like the one in the junk yard, here is the pic.
  I have not removed a 3rd member before so I don't know what the straight gear is for

The straight gear is most likely a "tone ring" for an anti lock brake system - as to the locker question - I'm sure some guys can tell by looking, but I'm not one of them.

Hi

I will begin by stating I am not an expert, but do have knowledge on the matter. You should be able to tell if your 3rd member has a locker in it or not. Inside the differential casing or carrier that the ring gear is bolted to, meaning the casing between the bearings on both sides to the ring gear, you should see 4 metal "wheels" with teeth on them, or spider gear. The "wheels" are inside this carrier and mesh together in an open differential. such as in the following link:

http://www.quadratec.com/Assets/Knowledgebase/Image/opendiff.jpg

In a locking differential the setup will look distinctly different in almost all cases, perhaps the Lock-Rite being the most similar to open diff.

http://www.film.queensu.ca/cj3b/Photos/Tech/Axles/LockRight.jpg

But just try searching for both open and locked differentials on Google for the particular setup you are interested in and you should come up with some pictures for reference. hope this helps you.

Best regards,
Tryggvi

Unfortunately - it's not that easy - the gears are not always visible



This is a Suzuki Jimny differential.



This is the same Suzuki Jimny differential with a Detroit EZ Locker installed - the ring gear still needs to be reinstalled.

The images were taken from this thread on installing an EZ locker.

Thanks i will have to take a closer look & check them out

Unfortunately - it's not that easy - the gears are not always visible



This is a Suzuki Jimny differential.



This is the same Suzuki Jimny differential with a Detroit EZ Locker installed - the ring gear still needs to be reinstalled.

The images were taken from this thread on installing an EZ locker.

But the other half of the carrier has little "windows" in it where you can see the gears inside the carrier.  So if you know what you are looking for, you can tell if there is a locker in it.