Does anyone know of a replacement diff or transmission for a Traxxas SRT?

[Smuffy]

I tried google, to no real luck, and this forum won't let you search for 3 character words(SRT etc) so I have no clue where to look. My local parts shops don't have much available and this diff just doesn't have any life left in it. I'd be ecstatic to find something a bit newer, maybe Revo spec with metal gears but I'm not keeping my fingers crossed. If anyone can confirm a swappable setup, it would be most appreciated. I hate to just see her sitting around like my Hawk 2