Maybe A Bug
 

I can't seem to find any info on this, but in 5.02+, the controls for removing the vendors in the traveler's tundra mammoth are gone. I think they changed the vehicle mechanics for this mount. Hope this helps.

From the other discussion about this, it seems to be a bug. Spiel is working on it though. The other discussion is here: http://www.wowinterface.com/forums/s...ad.php?t=22497