Whom to trust to do the work is entirely dependent on the individual mechanic's qualifications and quality of work....supraboytt said:
Any toyota dealer should carry the diff fluid and the transmission fluid, but most of them don't know which is the correct fliud.
For the diff, you need: GL-5 SAE 90 gear lube. (No limited slip additive necessary, actually Toyota advises against using one in the Torsen).
For the 6-sp transmission, you need: Toyota V160 gear lube.