2-way diff making buzzing noise

[Stripes]

my friend works at a transmission shop and installed my 2-way for me. it has new bearings and seals and i did the whole figure 8 break in process for 40 minutes but when driving, after about 5 minutes i hear a buzzing noise coming from the diff as if the gear is buzzing the diff cover. not sure what it is but if anyone could help that'd be cool

[evildky]

probably just cluthc chatter, I've always heard you should change the fluid at about 1k miles and that it helps, but generally an aftermarket led especially one wht a 1 2 or 3 way activator is gonna make some noise