Somebody has to have some insight on this...!
I have been searching for weeks for information on this, and my S1 and personnel section have been no help either...

I was prior service, and recently reenlisted with over a 4 year break in service. Upon reenlisting, what happens to my prior MOS? I can find no regulations specifically concerning this...but that also means I can find no regulations that say it expires or is lost after a break in service.

As far as I can tell, I should still be technically MOSQ'ed in my prior MOS until retrained, and hold that as my PMOS until granted another MOS.

Anybody have any information or experience with this?? Thank you.

I don't have regulatory guidance for you, but the bottom line if you are qualified in your previous MOS and have the training certificate or DD214 to prove it, that is your Secondary MOS. For example, my SMOS is 13M20 (not 30 because I never held the rank of SSG in that MOS and therefore am not qualified on the 30 level tasks). When I was going through the reclass process my MOS was still 13M20 not 97E20. You are in the same boat.