What could break free and be grinding in the diff?

[triggz]

Last night when I took my car out all of a sudden this loud deep wirring noise started. It sounds like when you run over a coke can with a bicycle tire and it rubs against the tire. I put the rear on jack stands today and its coming from the differential, if you place your hand on the dif cover you can feel something flapping against it as the ring gear rubs on it (like a card in a bicycle wheel).

What possible things could be broken? Torque application makes the noise change some, but its mostly directly related to speed. Could a clutch plate be shattered and laying against the cover?

This is a 2000 GT auto with 81k, 4.10 gears since about 40k. Never had any problems.. Although *occasionally* when initially starting to back of the driveway after sitting overnight there would be a light 'pop', I couldnt discern if it was just the rotors being stuck or the rear since my rear brakes are trashed.



edit:

Here is a video clip. When the car is taching high rpm and the noise is low, its in 1st gear at 10-15mph. It gets substantially louder when put into 2nd and about 20mph.

http://media.putfile.com/Differential-grind

 

[hotmustang331]

Time too pull the cover off and find out....whatever it is, it cant be a good thing. I would stop driving it and check it out...like right now haha.

 

[BooWFO]

^^^
things that jump to mind.
bolts backed out on carrier support
Bearings went south FAST
Ring gear snapped.
diff went south although usually the car won't move when that happens
c-clip poped off although usually an axle will exit the car.

 

[BlackenedSVT]

yeah buy more gear oil and take the diff cover off, and PRAY its nothing major.....

 

[MBDiagMan]

Yes, exploratory surgery is the only step to take next.

 

[BurningRubber]

Wow, thats bad. Yank that cover asap.

 

[Mike97gt]

if this thing still moves it's probally the S-spring for the trac-lok

 

[98V6 K.I.T.T.]

Atleast the exhaust sounds good......but yeah, whatever it is, that can't be good. Let's hope it's nothing major.

 

[BlackenedSVT]

if this thing still moves it's probally the S-spring for the trac-lok

Nooooo way... those rear diff gears would stay together while driving with that springs gone???? How could that even fall out when its held in place by the big pin and then that pin is locked in place by that 8mm bolt...

Or wait, i think that pin just passes through actually, so it technically wouldn't stop it from falling out, so i guess nevermind.

 

[DTMach1]

Well lets see...

To me that sounds like a couple things...you're either almost completely out of fluid, you lost a bearing, your gears were set up way wrong, or you lost some teeth on the ring and pinion gear.

Eitherway, don't drive your car! Get an oil pan, pop that cover off and take a good look around. Remember when inspecting the gears to check EVERY tooth not just the ones you can see (ie spin the wheels).

Oh yeah and post pics!

 

[the98stang]

Time for a 31 spline diff

 

[BurningRubber]

I wanna see some pics, lol.

 

[Pennywise2]

Time too pull the cover off and find out....whatever it is, it cant be a good thing. I would stop driving it and check it out...like right now haha.

You should seriously check that out asap.
Sounds to me that your bearings went south.
If so look forward to a rebuild of your rear end.
Hope for the best.

 

[Mike97gt]

Nooooo way... those rear diff gears would stay together while driving with that springs gone???? How could that even fall out when its held in place by the big pin and then that pin is locked in place by that 8mm bolt...

Or wait, i think that pin just passes through actually, so it technically wouldn't stop it from falling out, so i guess nevermind.

I have seen the spring crack in half before.. the side gears would be held in place still by the upper and lower side gears.. as long as all four gears and the center pin are intact the side gars will not fall out even without the spring.

 

[triggz]

Took it apart today and found some chunks floating around and there are several damaged teeth in at least one spider gear. Its kind of hard to tell without cleaning all the fluid off, but I think the damage is limited to the spider gears, possibly the side gears. The ring and pinion dont appear damaged.

View attachment 427286

View attachment 427288

more: http://s34.photobucket.com/albums/d131/triggzzz/Differential Damage/


if you dont know what you're looking at:

 

[BlackenedSVT]

hmm thats interesting. Did you have gears put in recently that the install went wrong on? I dont see how something like that could just happen

 

[triggz]

hmm thats interesting. Did you have gears put in recently that the install went wrong on? I dont see how something like that could just happen

I have 40,000 miles on the gears and no problems. Maybe the main cap bolts have backed out and caused slack somehow?