Bad rear end oil. Are bearings bad??

[pqtiii]

The back of the car started swaying when I shifted gears going down the highway. I check the oil and it was solid black. I assume the clutches are totally gone after about 200 passes at the track. I noticed that one of my wheels would stop spinning during a burn out towards the end.

Does the clutch particles in the oil cause the bearing to go bad. I need to change the clutch pack, so should I replace all of the bearings too?

Thanks
pt

 

[GrnBullitt08]

Have you taken the rear apart to look at it? After 200 track passes I would assume that something had to give. Clutch packs would be a good start...are you still running on the stock 8.8 diff and axles or have you upgraded?

 

[pqtiii]

Everything is stock. I changed gears about 8000 miles ago. It started making noises a few months ago so I thought it might need more additive. That is when I discovered the black oil. The swaying made me park it.

pt

 

[GrnBullitt08]

If your gonna start replacing things in the rear I would just go ahead and upgrade the differential while your at it, upgraded axles, add carbon clutch packs, and buy a rebuild kit just to cover all the bases. Im sure your making some decent power with that TT setup, and once you start adding more power the upgrade drivetrain will be essential...Im guessing your running a 3.27-3.55 gear?

 

[Rubrignitz]

I agree with grnbullitt. I had Richmond 3.98's installed in my car last week and the guy said my trac-lok was probably in good shape but I'm having some of the same problems I had with the 4.10's (noise..likely carrier noise etc). I looked at the axle splines when he had it apart and they looked worn to me. That's on a 320whp car with 60k miles so I would say if you're going to do it, do it right. New axles, gearset, eaton with carbon clutch packs and all bearings. I'm out ~$800 and will probably take the thing apart again in 6 months to have an eaton installed with new axles.

 

[white05gt]

Why would he need new axles, the stock axles have proven themselves? Odds are he just needs to upgrade the differential and not replace everything in the rearend.

 

[ixtlan]

The Black you speak of most likely is the phosphor coating coming off the gears. You should have dumped your oil at 500 miles after the gear change. Does the oil smell burnt? Or like a burnt clutch smells?
That would be a sign of things not going so well inside.

 

[Vapour Trails]

Why would he need new axles, the stock axles have proven themselves? Odds are he just needs to upgrade the differential and not replace everything in the rearend.

Around here if you need an air filter change most people will tell you to upgrade to a forged shortblock while you are at it.

I'm really not sure if the OP even has a problem. The oil is dark and two hundred passes isn't that much. Also, I don't see what that has to do with the car swaying. I'd look at the rear suspension.

 

[mrdeath2000]

+1 vapor trails. maybe a bolt is loose/gone on the rear suspension

check LCA, UCA, swaybar, panhard bar, shocks, springs.
jack up the rear and try and pull an axle out with the tire on

 

[Rubrignitz]

The Black you speak of most likely is the phosphor coating coming off the gears. You should have dumped your oil at 500 miles after the gear change.

I swapped mine this weekend and it was pretty dark. Looked good other than that, no flakes or particles. Guess I'm ok there. Time to look at my driveshaft, u-joints etc for the noise.

 

[ixtlan]

The coating is supposed to come off.
It doesn't flake but more dissolves or wears off the contact areas..
Wanted to make sure I wasn't misunderstood.
Nothing wrong with it, just makes your oil blackish grey.

 

[one eyed willy]

i looked at mine yesterday.......gear oil was black, or very gray to say the least.


do our rear end plugs have a magnet built into them? looked like it, and i had alot of gray matter built up on it. whipped it off and it reminded me of rtv that was not hard yet.

 

[kevinatfms]

the rear should not sway. check for loose bolts/nuts. as for your rear end, black oil is fine as long as it hasnt lost its viscosity. check for particles in the fluid that would indicate anything with your clutch packs have come apart.

also how many miles on the rear?

 

[Rubrignitz]

The rear fill plug is magnetic. The grayish mush on the plug is fine metallic particles. I was just stating that if you go into the diff rebuild it right the first time. Hell if I could afford it I would swap a forged assy in with my air cleaner ;-).

Swaying is a pretty generic term. Is it fishtailing under power? You could just need new rear dampers.

 

[pqtiii]

The rear fill plug is magnetic. The grayish mush on the plug is fine metallic particles. I was just stating that if you go into the diff rebuild it right the first time. Hell if I could afford it I would swap a forged assy in with my air cleaner ;-).

Swaying is a pretty generic term. Is it fishtailing under power? You could just need new rear dampers.

Not fishtailing. It fells as if the rearend moves a little to the right than back to left only when I shift going straight. Driving down the road in a gear feels fine.

 

[Rubrignitz]

After 200 passes and you noticing the side losing traction it does appear that your diff is toast. Rather than rebuild the trak-lok I would recommend going Eaton posi with the carbon clutch packs. I'm not saying you *have* to swap some new axles in but have the guy check them out when the diff is apart.

Check your suspension too. With the car parked and parking brake engaged push the rear of the car from side to side and forward on the rear of the car to see if there is any play. I did this when I had some issues with aftermarket rear control arms and there was side to side play in the bushings.

 

[pqtiii]

After 200 passes and you noticing the side losing traction it does appear that your diff is toast. Rather than rebuild the trak-lok I would recommend going Eaton posi with the carbon clutch packs. I'm not saying you *have* to swap some new axles in but have the guy check them out when the diff is apart.

Check your suspension too. With the car parked and parking brake engaged push the rear of the car from side to side and forward on the rear of the car to see if there is any play. I did this when I had some issues with aftermarket rear control arms and there was side to side play in the bushings.

I pushed the car side to side from both sides and it seems solid. I even jacked up the rear and pulled on both tires. I could feel the normal C clip end play, but that was it.

What gets "toasted" in the rear to make this happen?

 

[Rubrignitz]

The clutch packs in the trak-lok carrier. This will give you a bit of explanation. I tried to locate a good exploded view of the diff but having trouble finding one. Do you notice any shuddering/noise when turning?

http://www.youtube.com/watch?v=0GsLDg3C6Hc

 

[2014_GT]

Is your car lowered? And, did you replace the stock pan-hard with an adjustable one? Could be something simple as the pan-hard bushings going or a loose bolt in your suspension. My gut tells me it's not your diff.

On a different note, the oil in your rear-end does lubricate your bearings. So, if the oil is mucked up, then it MAY affect them. Always a good idea to change oil after 500 miles past a gear-change.

 

[iwaxmyjimmy]

Is your car lowered? And, did you replace the stock pan-hard with an adjustable one? Could be something simple as the pan-hard bushings going or a loose bolt in your suspension. My gut tells me it's not your diff.

On a different note, the oil in your rear-end does lubricate your bearings. So, if the oil is mucked up, then it MAY affect them. Always a good idea to change oil after 500 miles past a gear-change.

No, black rearend oil has no effect on bearings just change it. Now if it came out looking like silver paint or you noticed a roaring noise then you have some bearing problems. How much torque is your car producing?? I would research carriers for yourself, call the manufactures, and explain to them what you intend on doing with the car. Everyone can say hey use this or that, but you should research it for yourself. Google can do wonders for that also.