I have a 2003 4x4 Silverado DMAX/ALLY. Is the rear end a fully open diff in 4x4. Limited Slip, or Locker? Also who makes it? Thanks i got a bet with a friend and i wanna be right.

11.5 inch ring gear....made by AAM (american axle manufacturing?)
It would depend on if you have the G80 option or not..
G80 = limited slip
No G80 = open differential
It doesn't matter if you're in 4WD or not as to what the rear end is going to do...

I thought G80 =Eaton locker. I don't beleive 4wd makes any difference.

I have the Ultra Rare G-80 that has been 'Juiced'

Acts like an open diff 24/7

For some reason I am believing that you can only get the G80 with the Duramax package???

For some reason I am believing that you can only get the G80 with the Duramax package??? Nope...
You can get it with almost, if not, every truck gm offers

For some reason I am believing that you can only get the G80 with the Duramax package???
i think he ment that the only rearend they put in the dmax is the G80. i know you can get it in a 1500 even but as an option. the G80 I thought was standard on the dmax though along with the allison.

Duramaximizer, ya what you said. Thanks.

no problem glad to help

Some trucks were made without the G80 posi option. Stupid dealers ordering them in without posi. I know a guy that bought one not realizing it. And yes, I'm talking about 2500HD trucks.

The G-80 option has been around since 1973! The eaton automatic locking differential or Gov Loc as those of us in the know like to call them, sometimes work well and sometimes they don't. To know if it works well you have to understand the theory of operation. There are two clutch packs, one for each side gear, one side gear is a two piece unit that has interlocking cams. Then there is a small governor gear and another piece that looks like a flywheel ring gear that is attached to one half of the interlocking cam gear. When one wheel begins to slip the governor gear(the one that looks like a starter drive gear) spins the cam gear in the opposite direction of the side gear forcing the side gear against the clutches and against the case, causing full lock up. Now for the down side, as a design feature, the difference in speed between the tires must be about 100 rpm's (this keeps the unit from locking while going around corners) and the other fickle part is the governor weights on the locking mechanism, it will not allow full lock up at speeds over 25 mph. Propper test sequence is to jack up both rear wheels, place transmission in gear and bring speed up to about 10 mph, grab one e-brake cable and apply that brake, within several seconds, the differential should lock and force both tires to spin as long as there is pressure. Take off the pressure and the process has to be repeated again. These units have always worked well in the full floater rear axles, but in the light duty axles, they tend to self destruct do to the locking nature. On the light duty versions it is common to see teeth missing from the outer ring style gear or broken spiders. I have even seen one full floater 14 bolt that finally stripped all of the teeth off of the 3 spiders. The truck would sit still with the drive shaft turning and then all of the sudden lurch forward when the locking mechanism engaged.

Propper oil is a must with these locking diffs, and I preffer redline 80/140 synthetic. So next time you want to see if yours is working the right way, test it like I have explained, if it still doesn't work, pop the cover off and look for broken pieces. The biggest problem I have with these diffs is that when you need both tires pulling, thel last thing you want is to let one tire dig a hole before the other locks in, because then you have two holes and no forward movement. One other trick that can be used with these diffs is to lightly apply the e-brake to help load the unit. I have used this with success even with one tire a foot off of the ground, and when it locked, I drove out! Now I just use detroits ):h ):h :exactly:

So, Mr. Camilleri, My p/u has an open diff; no G80 code listed. Runs one legged; got the tire patches to prove it. I want a good solid 'limited slip' unit to install. I understand Eaton's E-Locker doesnt fit the rear end? What will? You mentioned you use only Detroits now... Recommendations? What about the front diff in these 4X4's? What fits these? Eaton E-Locker here? TIA, Brock in Montana...

Unfortunately the only option so far is the eaton factory posi. Dodge also has a different version of all gear posi, but the gm version seems to work better. Contact Tractech and see if they have any plans on making a detroit for the AA 11.5. Watch ebay motors, I saw a practically new factory posi for a 11.5 rear axle go for around 100.00, a steal. Also contact ARB, maybe they have plans to make an air locker. ARB should have an air locker available for the front.;)

does oil viscosity affect the counter weights and how fast the locker engages?
I put on a mag-hytec, with 80-90 and some lucas. the locker doesn't seem to hold as well.

It is a lot easier to just get on it from a stop on gravel. It locks very fast according to the tracks. Later! Frank

Oil weight doesn't seem to have a lot to do with operation unless it is very cold. More so it has to do with the propper lube, GL-5/GL-6 the oil needs to meet limited slip requirements so that the clutches can grab.;)

I have self destructed 2 of these G80's in my 90. I am not a fan of the light duty Eatons. :thumbsdow Good summary though!

The G-80's as used in 10 bolts are weak and will self destruct if abused. The G-80's used in full floating applications are a lot stronger and normally hold up very well.;)

It is possible to get a Dmax without G80.
How?
The G80 comes as an option, either as a line item or with the "Heavy Duty Power Pack",
which includes G80+Dmax+Allison. If you want Dmax+Allison with no G80, it actually costs $1000 MORE than to get it with the G80. With a manual transmission, you must order the G80 as a sep. line item.