rear end/ gear pack needs to be replaced

My 05 Tacoma has a gear pack (aftermarket i guess installed by previous owner )
when i turn the rear end is popping
My mechanic put in correct additive in last yr & it solved the problem. Now its making notice again & the fluid didn't correct the problem.
Have any of y'all had any experience with a gear pack or having to replace the rear end on a Tacoma. Thank you in advance

 

TRD sport means you have Mechanical Limited slip. They should not pop. So far no additive makes them work (some last a year some last few months)
So far mine worked with regular DINO lucas oil. I sugest before anything get regular gear oil from Lucas I used 85-140 in mine and that makes limited slip come back to life every time.

 

its possible the clutch pack needs to be replaced.