It's got me tossed why so many feel that they have to have a TXPDR code. Won't the bloody plane fly without it?
If ATS don't give a code on taxi, then use 3000 (or appropriate for ops). You'll get it eventually but there is no need of it close to AYQ, GOV, ASP and much of the rest of the continent.
If
in a radar environment, and the code hasn't been assigned, I could understand asking.