I just bought a 2001 Toyota Tacoma 4x4 TRD SR5 Double Cab truck. I was under the impression that all the newer 4x4 SR5's had the Rear Differential lock that came stock. Can somebody break it down to me what models came with what? I'm really sad it doesn't have it

 

Someobody else can probably give you a more accurate answer, but AFAIK it was an option for most models that year.