I have a 2004 Silverado 2 wheel drive ext. cab. I'm wondering what the difference is between a locking differential and a limited slip differential. My truck has the locking differential (RPO code G80 - locking differential heavy duty)?

I noted I have very good traction for winter driving here in Wisconsin with my 2wd and my 20 inch Goodyear tires.

Are there disadvantages to the locking versus limited slip units?

There's no difference that I am aware of. The terms locking, closed, limited slip, and positraction are used interchangeably AFAIK

There's no difference that I am aware of. The terms locking, closed, limited slip, and positraction are used interchangeably AFAIK

But why have 2 different RPO codes then - limited slip differential is a G86 while the locking differential is a G80. I sense there must be some differences. I'm "guessing" the positraction concept is like the locking differential I have - while the limited slip is something different. Too many bright people read this forum - somebody must know a bunch about it :smile:

I think I read on the Eaton site that the Limited Slip is activated via input from the drive shaft and the Locking is via loss of traction on one side or the other. Again "I think".

limited slip has clutches in it, and requires a "limited slip" lub additive. The "locking" rear is quite different and does just as it's name implies--it locks--no clutches! They also use "g80" for the 2500hd duramax I had, and that rear is four times the "g80" in a half ton!

if u dont like ur locker ill take it and u can have the one-wheel-spinning piece of crap in my truck lol.

Better traction comes in different forms. Straight off the line WOT open diff will spin for a while and takes less power/friction to run. The positrac allows slip but has to sense slip before engaging. The locker pretty much is both sides are engaged at all times thus taking up more power, minimal as it is but at an instants notice will keep the rear stable. The locker will allow some slip around corners but very little, very. As tought to me by teacher(master) who races.

Better traction comes in different forms. Straight off the line WOT open diff will spin for a while and takes less power/friction to run. The positrac allows slip but has to sense slip before engaging. The locker pretty much is both sides are engaged at all times thus taking up more power, minimal as it is but at an instants notice will keep the rear stable. The locker will allow some slip around corners but very little, very. As tought to me by teacher(master) who races.

Yeah, I can't hardly turn a corner w/o chirping the tire on mine... gets kinda annoying.

If anyone is unhappy with there locker I will drive over and do the swap, open 3.42, to keep you happy....

Nope, not that annoyed. That crap is awesome in the rain about not losing traction, White Lightening knows...

limited slip has clutches in it, and requires a "limited slip" lub additive. The "locking" rear is quite different and does just as it's name implies--it locks--no clutches! They also use "g80" for the 2500hd duramax I had, and that rear is four times the "g80" in a half ton!
Very true. A "locking diff" must either be mechanically, electrically, or air activated. A good example is the new Jeep Rubicon or Dodge Power Wagon. A "limited slip" or "posi-traction" is just that, clutches activate within. They are activated due to each tire turning at a different ratio or speed, A "locked" axle doesn't care, they (tires) turn at the same speed all the time. If you have a true 'locker" you would know because the rear end (or front end in some cases) will resemble the sound of a .22 rifle when cornering on pavement. POP!

Very true. A "locking diff" must either be mechanically, electrically, or air activated. A good example is the new Jeep Rubicon or Dodge Power Wagon. A "limited slip" or "posi-traction" is just that, clutches activate within. They are activated due to each tire turning at a different ratio or speed, A "locked" axle doesn't care, they (tires) turn at the same speed all the time. If you have a true 'locker" you would know because the rear end (or front end in some cases) will resemble the sound of a .22 rifle when cornering on pavement. POP!

Any other input from any of you? I was actually getting ready to ask the same question. My 6.0 HD also has the G80 locker with 4.10 ratio. The true lockers that I'm used to do not have clutches, and have to unhook mechanically to corner, and can be heard. Mine is smooth and quiet when cool. However, after driven on the highway, the first couple of turns from a stop produces a shuttering, chattering sensation from the diff. that is quite noticable. Sure feels like clutches to me, and if so, a differential lube change is in order.

Actually, on my breakdown of RPO codes, G80 reads "Axle Positraction Limited Slip"

Actually, on my breakdown of RPO codes, G80 reads "Axle Positraction Limited Slip"

When I ran my VIN on GM VIS it came up as G80 / Locking Differential- Rear Axle.

My guess is that GM's version is just another name for limited slip, not a true locker.

No clutches on a true "locker". They use metal teeth that mesh together--locked. The only way they can slip is when the teeth basically skip a cog (causing the BANG!). This should help:
http://www.powertrax.com/nsexploded.html

When I ran my VIN on GM VIS it came up as G80 / Locking Differential- Rear Axle.

My guess is that GM's version is just another name for limited slip, not a true locker.

My 2004 Silverado has a RPO code of G80.

Directly from the RPO Codes guide is the following:
"G80 Differential, locking, heavy-duty, rear
G86 Differential, limited slip, heavy-duty, rear"

Get the RPO Detail print out from the dealer to verify exactly what you have. Some codes were different to models in the same year.

Also you can get the mechanics in the dealers shop to tell you what the difference is, they have torn down a few I bet.

No clutches on a true "locker". They use metal teeth that mesh together--locked. The only way they can slip is when the teeth basically skip a cog (causing the BANG!). This should help:
http://www.powertrax.com/nsexploded.html

Right. These G80's must be basically just a limited slip simply named "locker" by GM. Correct?

Right. These G80's must be basically just a limited slip simply named "locker" by GM. Correct?

From my understanding - the G86 is the limited slip version (not positration but limited slip) - while the G80 (positraction) is the type used in the SS and in my v.h.o. 2wd truck. My understanding (from others) is that positration is a better traction method than is limited slip - and is often used in heavier duty or higher powered vehicles).

From my understanding - the G86 is the limited slip version (not positration but limited slip) - while the G80 (positraction) is the type used in the SS and in my v.h.o. 2wd truck. My understanding (from others) is that positration is a better traction method than is limited slip - and is often used in heavier duty or higher powered vehicles).

Positraction and Limited Slip are two names for the same thing. The G80 locker also uses clutches, but a flyweight and cam setup to operate the clutches. Check this link, complete with video.

http://www.traction.eaton.com/prod2.htm

Positraction and Limited Slip are two names for the same thing. The G80 locker also uses clutches, but a flyweight and cam setup to operate the clutches. Check this link, complete with video.

http://www.traction.eaton.com/prod2.htm

I also did a search engine of "G80 locking differential" and found forums where complaints of the Eaton locker (G80) was chattering on turns when hot. The fix (according to GM, according to this forum) was to replace the diff fluid with synthetic, but DO NOT add the friction modifier additive to this G80 setup. If so, it should be flushed, as the discs are metal and the additive can cause them to glaze over.

Apparently GM's locker and limited slip are two different types of differentials.

I think if more people new of and understood the benefits of LSD's and locking diffs, there would be a lot fewer 4wd vehicles on the road.

you got me thinkin now, my duramax G80 I put mobil 1 syn in and it acted fine as well as the G80 in my '99 1/2 ton, but my '97 formula firebird when I put just the mobil 1 in made a hellava racket until I put in a bottle of the "limited slip lube"! Def. two different types of rears!

The locking diff in the chevy rear on my truck is a limited slip posi. If it were a locker, like everyone has said, if would be way annoying when turning. The limited slip allows for just that--limited slip of each of the rear wheels. A locker or spool is terrible on turns, especially tight parking lot manuevers. It allows for no slip, which is great for drag racing or off-road traction, but sucks in everyday driving.

later

I had a 1970 Chevy C-10 with a Posi rear. If I didn't use the GM addative, it sounded like I had timing gears at any speed above 40. Sounded kinda cool, but after having to replace the rear, it wasn't so cool. I was also 16 back then. Just be sure to use the $$$$ bottle of addative from GM, it will save ya.

The locking diff in the chevy rear on my truck is a limited slip posi. If it were a locker, like everyone has said, if would be way annoying when turning. The limited slip allows for just that--limited slip of each of the rear wheels. A locker or spool is terrible on turns, especially tight parking lot manuevers. It allows for no slip, which is great for drag racing or off-road traction, but sucks in everyday driving.

later

This is the LOCKER that's in the Chevy, like twomorestrokes said
http://www.traction.eaton.com/prod2.htm
Read the page, it is a locker; Eaton has a seperate pager for their posi/LSD setup.

For Clutch-Type Limited Slip
Go to http://auto.howstuffworks.com/differential8.htm
For Locking and Torsen® diffs
go to http://auto.howstuffworks.com/differential10.htm

GM doesnt use a "true" locker cus it only engages if the drive weel slips.To demonstrate find some dirt and do a burn out but slowly give it gas and listen after about 1-2 revolutions of the drive tire "left weel" you will here a ping sond and the right tire will start to spin if you have a locker if not the left will just keep spinning.

The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids

The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.

These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.

However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.
This is what GM uses in the trucks

That is how AUTO 4X4 works also
The silverado SS has Viscous Coupling http://auto.howstuffworks.com/differential9.htm

You might want to try applying a little brake at the time you find your Torsen diff spinning one wheel uselessly. It might just help.