Hi guys, running a 3.62 sierra LSD diff.

Firstly, not sure what drive shaft style I have (has "teeth" on the out puts of the diff but they do not interlock - about an inch gap)

my car has delevloped a low speed knocking from the the rear passenger side. (may be central but hard to tell)

i noticed my diff had lost some oil through breathing so topped that up yesterday (didnt need it) and the noise is still there.

its like a fluttering. i keep grabbing the pass seat harness thinking its them moving but its not. finally, i can never provoke the noise and it doesnt seem to come on when coasting.

got ring in 4 weeks and really want to get it sorted.

man i wish i built my car someties so i had more of an idea.

I have an R1 engine. there is no drone or whine from the diff and it still pulls bloody hard so i do not suspect the engine prop to be the issue