Re: Rear-end failure modes?

[Simon Favre <simon@domain.elided>]

Since your car is a '74 GTV, the most likely cause of the silt on
the diff drain plug is the LSD. The clutch pack in the LSD does
wear over time. The older, non-LSD diffs didn't produce a lot of
silt. Remember tho, the diff oil is unfiltered. Diff problems
don't produce driveline vibrations, they make groaning or howling
noises, until the very end, when they go CLUNK! ;=( If the inboard
bearings were bad, you might see damage on the crown gear teeth,
which can be seen thru the fill plug. A small flex-light and an
inspection mirror will help.

The wheel bearings are not easy to evaluate just by grabbing the
disc. Only with the full width of the wheel and tire will you get
enough leverage to really tell if the bearings are loose. Once the
axles are out, you can feel the bearing directly, spin it, and see
what kind of shape it's in. These are sealed bearings, so if the
seals are leaking, the bearing is soon to go bad. If you spin the
bearing and hear clicking noises, the bearing is going. If the
outer race wobbles in your hand, the bearing is gone. On a car this
old, the wheel bearings are definitely a consumable item...

------------------------------