So I have an 05 ECSB Chevy. I bought it off my friend, who had put two rear ends in it in the time he owned it. Obviously the first bad one was from the factory, and the 2nd one that broke was (i'm assuming) another one from the factory since it was under warranty. However, I don't know if they were limited slips or lockers (I'm still confused after doing tons of reading on this site as to what comes in these trucks stock). What I do know is when the 2nd one blew, He had it replaced at a local garage, and after some research I believe it is an Eaton limited slip (due to the fact that there are springs showing clearly in the carrier when I took the cover off, and I don't see any type of locking mechanism). The problem I'm have is...I get a one tire fire now. I bought the truck about a month after the latest rearend was put in, and beat it a decent amount but not too much, and it let go pretty quick. That was about 6 months ago and I just pulled the cover cause I'm starting to wonder when it will fully let go. I put some friction additive in when I put the new fluid in the other day, however it still spins one tire, and only locks sometimes in the snow (we just had a storm today). What is wrong?

 

sounds to me like you need a truetrac just give up on the g80 its

 

X2. You need at 14 bolt!!!

 

x2 i have heard some say you dont need the modifiyer with the g80 and some say you do need it

 

I know I should upgrade. Once I get some $ I'm gonna, but until then, will it be ok since I just changed the fluid? It didnt seem like anything was really floating around in there. I just wanna make sure it's not gonna let go completely on me when I'm making long trips away from home to go snowmobiling this winter...

 

Since you said you can see springs it sounds like an Eaton Posi - the aftermarket unit not the factory G80.
On snow or any slick conditions with these it's possible to get one-wheel spin. It has to do with the way they work. Eaton posis are torque biased not left-right rpm delta like the G80. In slick conditions it's often difficult to get the unit to see enough torque for the clutches to engage.
One trick to get these to lock up in slick conditions where you need the traction of both wheels to pull out of being stuck (like on snow or boat ramps) is to engage the parking brake. The resistance from the brakes will provide the needed torque to activate the mechanism.
True Eaton Posis do need limited slip additive and have a wide range of compatible viscosities of gear oil that can be used, all they way up to 75-140.

 

Hmm, never knew that that was how they worked, thanks for the info. I used to be able to powerbrake it and have both tires spin almost instantly, but not its one wheel. One time it worked fine, the next time it was a one legger...and it never gave me an indication that it was gonna let go...it just did.

 

If it won't leave two stripes powerbraking it needs a rebuild. Unlike the disposable G80, an Eaton posi can be fully rebuilt. In doing that you also have the option of installing tighter springs.

 

sounds like the clutches are burnt out of it. just rebuild it and be sure to put some additive in it!

 

Just as James B. said, you can just purchase a rebuild kit for the Eaton LSD and be on your way. While as he also mentioned, there are different spring kits available, I would stick with the standard replacement pieces for your particular truck. The standard springs in the Eaton LSD is 400lbs, while there are 200lb and 800lb kits available. The 800lb kits are for more extreme use, where a person is pushing the LSD about as far as it should be taken before moving up to a locker. With the 800lb springs in place, you will notice more of a tendency to slip the inside tire going around wet corners or loose dirt/gravel and will require you to change the gear oil on a way more regular schedule. They would be a good choice if you planned on a good deal of track time. And as was also mentioned, you must use limited slip additive with the Eaton LSD units.

The part numbers for the 400lb & 800lb spring and plate kits are below:
29590-00S - 400lb Plates and Springs for 10-Bolt Eaton LSD
29591-00S - 800lb Plates and Springs for 10-Bolt Eaton LSD