I don't have any traxxas servos anymore but I remember taking it apart and comparing it to a Futaba S3003 (plastic). The internals looked similar. I did it about 3 years ago.
Castle Neu 1520 on 6S LiPo Powered Gmaxx (Nitro Killer)
Predator with OS .21TM
Supermaxx with Mach .26
Revo with OS .18TZ
Kyosho ST-RR Conversion
Ofna CR with Tekin ESC/Motor (2)