Locking Rear Diff

[holderp]

I may be ordering a Silverado in the next month or so.  I live down south and really don't need 4WD but I would like to have something other than the stock open diff for the one time a year when it does snow.  What kind of diff is GM's locking rear diff?  Is it really a limited slip or does it lock when slippage is detected?  Would I be better adding an aftermarket like a power-trax?

[Black02Silverado]

Not sure what GM calls it but from what I know it is not a locker, although I have hurd you could possibly order one. It is more on the lines of an Eaton with clutches inside.

 

Now the Powertrax is cool, and for what you need it for will work fine. I researched it a ton cause I was wanting to put it in my 65 Impala SS 396 but several shops, like DTS and Drive Train Direct didn't recommend it due to the fact that the open carrier is not made to hold up to a ton of torque. The Powertrax itself is bullet proof, but the open carrier becomes the week link.  

 

But for what you going to use it for it should be fine. The advantage to the Powertrax is that it locks up like a locker but gives you the streetable use of a limited slip.

 

[Shaners]

I don't know if this applies to the 2wd trucks, but RPO code G80 is a locking rear end in the 4wd trucks.  I have it in my truck and when it locks you can definatly feel it hit.  I know that mine locks solid, because I have had it lock on ice, and then made a turn on the dry pavement immediatly off the ice, and you could feel/hear that it was solidly locked...

[Black02Silverado]

Hey check out this link.

 

Eaton locker FAQ's

 

I learn something new every day on the net

 

Google is a killer search engine.

 

[95 Silverado]

The factory G80 posi unit, if it's the Gov-lock type, is a combination type unit, it uses clutches like the Eaton posi units, but it has a timer mechanism that disengages the clutches when the wheels aren't spinning, it acts like an open rear, but when one wheel spins the clutches are engaged and it acts like posi rear. Do a search on Ebay for "posi" you'll know the gov-lock when you see it, the posi's usually have a few springs in the center near the spider gears, the gov-lock will have weights, springs, and timer gears in there, which activate the locking mechanism.

[TxDoc]

Yes, GM offers a locker. The G80 is a locker. Dana axles can also be ordered with a limited slip. The differential is set up with a flyweight governor that responds to differences in wheel speeds, and disc packs that are mounted between the side gear and the case.

 

Whenever one wheel is spinning substantially faster than the other, the governor spins rapidly, causing the flyweight to open. That flyweight then catches on a latching bracket and the lockup process begins.

 

During lockup, a self-energized clutch system causes a cam plate to ramp against a side gear. This ramping action compresses those disc packs mentioned earlier. The ramping continues until both axles - and therefore both wheels - are spinning at the same speed. This is full lock, and it prevents any further wheel slip. (Note: Axle lockup can only occur at speeds below 20 mph.)

 

The entire lockup process takes about a split second, and is virtually unnoticeable by the average driver. When both wheels regain traction, unlocking occurs and things go back to normal.

 

 

 

For info, video, etc., go to ;

 

G80

 

Click for video

 

You can also buy an Eaton Electronic Locker, which you control:

 

E Locker

 

Basically, when the system is engaged, friction between an armature and an electromagnet apply force to a "ball ramp" mechanism. This forces the ball ramp's bearings out of their pockets and up the ramp.

 

That action, in turn, pushes the system's locking pins into matching holes located on the back of the side gear. That locks the axle, and drives torque to both wheels.

 

Click to see it

 

Click to see it from inside

 

Limited Slip info from Eaton:

Click here

 

With Eaton Posi, you prevent wheel slip before it can get started. To do that, carbon disc clutch packs preloaded by a central spring assembly are located behind each differential side gear.

 

When torque input increases (i.e., engine rpm's go up because you've got your foot in the throttle) the clamping load on the clutch packs goes up. That clamping load causes the clutch packs to grab, transferring power to the other wheel. The end result? Wheel slip is usually prevented.

 

The key here is that a limited-slip differential's power transfer is primarily based on input torque. So, with normal or light throttle applications on dry pavement, only the drive wheel receives torque, or power - just like an open differential.

 

While this is an excellent way to control traction in street rods, light duty pickups and all types of tarmac running racecars, it isn't the best solution for the serious off-road vehicle.

[TxDoc]

I forgot to add the Dana info. My Quadrasteer came with the Dana limited slip termed Hydra-Lok®.

 

The differential provides torque to any wheel that has good traction. The Hydra-Lok uses the same components for all applications, though it can be tuned to maximize a specific vehicle operation such as off-roading or high-performance handling. It can also be customized to operate above a predetermined rpm according to vehicle weight, wheelbase, and design parameters.

 

It  first appeared on the 1999 Jeep Grand Cherokee?was the first limited-slip differential to be successfully applied to both front and rear axles. Traditional limited-slip differentials are applied only to the rear axle because they typically cause the front wheels to lock together. Also, traditional limited-slip differentials are torque-sensing, in that the traction of the wheel on stable ground is determined by the torque of the spinning wheel. The Hydra-Lok, however, senses speed, so that the torque transferred to the wheel with traction is based on the speed of the spinning wheel.

 

Dana Corp.'s Spicer Light Axle Group has come up with a new device that promises the ultimate in four-wheel drive. Called Hydra-Lok, it automatically shuttles engine torque to any wheel that has good traction. Ordinary vehicles, including those with four-wheel drive, can't do that.

Hydra-Lok replaces the differential, a box of gears that goes in the middle of a drive axle. The differential allows the wheels at each end of the axle to turn at different speeds. You need that capability when you go around a corner, since the wheels on the outside trace a longer path than the ones on the inside and therefore must spin faster.

 

 Ordinary differentials send power to the wheel that spins faster. If the faster wheel has no grip--because it's on ice, for example--it gets all the torque anyway. You end up spinning your wheel and going nowhere fast.

 

Limited-slip differentials help curb that tendency, but they only work on the rear axle. Dana's new Hydra-Lok differential works equally well on both axles. The result: Your four-by-four keeps going even if both wheels on one side are off the ground.

 

 The differential has a hydraulic pump that senses wheel spin and applies pressure to a mechanism that transfers power to the wheel that slips.

[sgiangregorio]

I always get the G80 Locking Diff in my trucks, even with a 4wd unit. Do you tow boats at all? The locking diff can really help on a slippery ramp if you don't have 4wd. And I agree with Shaners and 95Silverado, when it locks, you feel the "thunk" of it engaging.

[rikhek]

My "4wd and rear end specialists" told me the G80 was junk and not to get it.  They said go with the Eaton posi unit.  I did and am happy.  I'm still a little confused with the G80.  Some people told me the "old" one was junk and the "new" one, designed and installed the last year or two is a redesigned unit and is good???  Bottom line is I bought my truck used w/neither.  I installed the Eaton and have no regrets.

 

Rick

[TxDoc]

The G80 is an Eaton. http://www.traction.eaton.com/prod2.htm

 

 

The Eaton Locker…When the Three Most Important Words Are Traction, Traction, Traction

You ever had your drive wheel slip off the road and into some mud? Or maybe snow or ice? Makes it hard to keep it going in a straight line, doesn't it? Traction just disappears…

 

What about a boat ramp? Ever been in a situation where one side of the ramp is all wet and slippery while the other side is dry as a bone? With an open differential, all you'll do is spin the wheels. And, even 4-wheel drive doesn't do much good in that situation.

 

Well - surprise - there's a solution. The Locker. The Eaton G80 Locking Rear Differential. This automatic unit, available for rear drive and 4-wheel drive vehicles, makes traction problems a thing of the past. The Locker makes towing large boats and campers a breeze.

 

It gives you the freedom to wander far from the beaten path in search of the perfect fishing hole, campsite or picnic area. It delivers traction and inspires confidence even in the nastiest off-road terrain.

 

A Quick Look At How It Works...

 

We'll start by pointing out that the Locker is a speed sensitive design. That is, it reacts to wheel slip by sensing when one wheel is spinning substantially faster than the other.

 

So, when you're cruising along on clean dry pavement, the locker operates like any regular open differential.

 

But, as soon as wheel slip happens, going forward or reverse, the locker immediately kicks in. Here's how.

 

The differential is set up with a flyweight governor that responds to differences in wheel speeds, and disc packs that are mounted between the side gear and the case.

 

Whenever one wheel is spinning substantially faster than the other, the governor spins rapidly, causing the flyweight to open. That flyweight then catches on a latching bracket and the lockup process begins.

 

During lockup, a self-energized clutch system causes a cam plate to ramp against a side gear. This ramping action compresses those disc packs mentioned earlier. The ramping continues until both axles - and therefore both wheels - are spinning at the same speed. This is full lock, and it prevents any further wheel slip. (Note: Axle lockup can only occur at speeds below 20 mph.)

 

The entire lockup process takes about a split second, and is virtually unnoticeable by the average driver. When both wheels regain traction, unlocking occurs and things go back to normal.

 

Want to see it work from the inside? Click here

 

Where can I buy a mechanical locker?

 

The Eaton Locker is option code G80 Locking Differential on GM light trucks and SUV's. Go to Chevrolet, GMC, Cadillac or Oldsmobile websites for more information.

 

So, what could make it better?

 

How about giving the driver complete control of when and what gets locked? The ability to lock the front axle, the rear axle or both axles with the touch of a button? OK, now you're talking ELocker™ Differential, the Electronic Locking front and/or rear differential…

[sgiangregorio]

Yeah, what TxDoc said.  

[Black02Silverado]

Yea what TxDoc said.

 

But wouldn't it been better to just make sure everyone went to the Eaton's web site and read it there, instead of typing it all out again in the forum?

 

Not that it was a bad thing and I enjoyed reading it again. Just thought it would have saved your fingers from all that typing. Not to mention they have a video of how both the G80 and the E Locker work.

 

I have them both. The G80 in the truck and the Eaton Posi in the 65 Impala.  Since they both work for what I need I love them both.  Although the E locker would be nice.

 

 

[TxDoc]

By typing, "yeah, what so and so said" makes me feel like I made someone look bad. That was not my intention. I did not type, that. It was on the Eaton site.  I simply cut and pasted it.  I don't know anything about an old vs new G80. So, I can learn something new here, too. I was searching and looking for Eaton info when I started getting ready to order my truck. I started from scratch and ran across that site. It was very helpful and informative.

 

 I am enlightened on a daily basis. I did not mean to come off as a "look,you are wrong, and,  this is the way it is"- and seem like a know-it-all jerk.  Sorry if that is what was conveyed.

[sgiangregorio]

I knew where it came from, and didn't think you were putting anyone down. I was coming from more of the "I'd buy that!" side than anything else when I said "what you said." just having some fun.

[95 Silverado]

The hydra-lok system mentioned above, is that a sytem with two open differentials but it uses the brake system to slow the spinning wheel, thereby transferring power to the wheel with traction, it uses the abs components to do this. Might be the reason for the name hydra-lok (hydraulic lock), It probably doesn't use the internal differential components at all.