quote:In addition, the stock bolts are serrated under the heads to 'dig in' and act as locks, but the surface of the ring gear is too hard for that to happen, so the serrations only act as surface-area reductions that contribute to loosening.
Once loose, the bolts begin to back out. Once out far enough they will impact some internal ZF surface and be snapped off. Maybe they then drop harmlessly into the pan, or they drop into the gears and ....
I know of one new owner who upon his first ZF fluid change heard a "PLOP" hit the drain pan. It was one bolt head. Fishing with a stiff wire, he started probing the ZF and soon had all ten bolt heads and 3-5 sections of bolt threads.
The ZF had been shifting fine and made no noises.
I know of one well-known vendor who dismisses the need to safety-wire the ZF. He told me this in a face-to-face conversation, not some second hand rumor.
Don't believe it.