[FlyingDutchman]

This is for my 1997 Z28. Has just over 90K on the clock. Stock T56 with stock 10-bolt 3.42s in it.


Case 1:
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I have been noticing a 'knocking' that I thought was in the front end every time I hit a bump. It has progressively gotten worse. When turning slowly into parking spaces (low speed, neutral) I can hear a clunk/metallic grind.

I assumed the knock was from the sway bar. So I replaced the front sway bar and end links after noticing a piece had broken off (look at the picture).



I thought the rear end might be grinding so I spun the wheels by hand and it seemed to be quiet. I also noticed the rear end has become a bit of a whiny PITA (literally). No play up and down by the rear or tail shaft. Only play is rotational which I believe is normal (right?).

That did not seem to solve the problem. So today I jacked up the car, shook the front wheels up and down, side to side etc. and could not replicate the 'knocking' I was experiencing while driving. Figured it could be a ball joint or something. Only noise I got was the brake pads shifting a bit. So, with the car resting on all four wheels, I grabbed the front passenger wheel with both hands and proceeded to shake the car back and forth. I hit a frequency in which I heard a not so healthy noise coming from the rear passenger wheel. Proceed to shake the rear wheel and find out there is play there. I assumed I was negligent in tightening my wheels and maybe had loosened and wrecked the wheel. When taking off the wheel none of the lugs were loose (in fact it took some muscle to loosen them). It appears the bearing may be shot. I can pull the wheel in-and-out maybe 1/16th or so? The moving part seems to be the rusted hub in the center. Below is a shot video so you can hear the noise and see what I am shaking.

This is the front (didn't have a picture of the rear on file), the rusty part im talking about is dead center of the rotor.


This is the rear wheel I am shaking. Not the best video, but the noise is audible.


To verify the rear end wasn't shot, I removed the other wheel which is nice and tight with no play anywhere.

So the question is ... what exactly is moving around? Wheel bearing? Something worse? What parts will I need to replace? Is it an entire assembly? Procedure for replacing bearing?



Case 2:
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My other question is pretty easy. While inspecting the rear, it appears the torque arm and front of the differential is covered in oil/dirt. One of the torque arm bolts had a drop of oil hanging off. I am assuming the pinion seal is leaking. Easy job to do myself? I need to get back to NJ from PA, I may just add enough fluid and do it over Thanksgiving break. What kind/type of oil/additive do I need? Is the fill hole the square drive bolt located maybe 3/4 up from the base of the differential?



Sorry for the lengthy read, prompt answers are greatly appreciated as I would like to tackle it this week.

Thanks in advance,

- Josh