G80 Locking Rear FAQ. How it works.

Conman · Post by **Conman** » Mon Jan 20, 2003 2:04 pm

Saw some info here:

http://www.weberchevrolet.com/tech.htm

From the website above:

Question:

2000 Silverado Ext Cab 4WD 5.3L At

Hello, my truck has the G80 locking differential with the 3.73 rear axle.

When there is a large difference in traction between the two rear wheels (I leave it in 2 HI), it seems I hear banging as it searches for traction. This appears to be coming from the inside of the differential. Is this normal? I understand that that Eaton changed the G80 spec for 2000 to a locker instead of a limited slip. Is it sturdy enough or will I end up repairing it when my warranty is out?

Answer:

Here's the skivy from the General regarding operation.

I hope this clears thing up.

Locking Differential Description and Operation

The locking differential consists of the following components:

Differential Carrier

Locking Differential Spider

2 Clutch Disc Sets

Locking Differential Side Gear

Locking Differential Clutch Disc Guide

Differential Side Gear Shim

Locking Differential Governor

Latching Bracket

Cam Plate

The locking differential allows for normal differential function as

indicated in the standard rear axle description. Additionally, the locking

differential uses multi-disc clutch packs and a speed sensitive engagement mechanism that locks both wheels together if 1 wheel spins excessively during slow vehicle operation. Under light loads, the clutch plates alone tend to lock the axle shafts to the differential case, and therefore, locking each other. This is due primarily to the gear separating the load developed on the right clutch pack. This induced clutch torque capacity resists motion between the side gear and the axle differential case. The differential allows the wheels to turn at different speeds while the axle shafts continue to transmit the driving force. Heavier throttle application will cause an axle speed difference. This action starts the full-lock feature of the unit. You can accomplish full-lock through the use of a heavyweight governor mechanism, a cam system and a multi-disc pack. The flyweights on the governor mechanism move outward in order to engage a latching bracket whenever the wheel-to-wheel speed varies by approximately 100 RPM or more. This action retards a cam which, in turn, compresses the

multi-disc clutch packs locking both of the side gears to the case. The 100 RPM wheel-to-wheel speed allows for cornering with the differential lockup. At vehicle speeds above approximately 32 km/h (20 mph), the latching bracket overcomes a spring preload and swings away from the flyweights. At this vehicle speed, or greater, the differential is designed not to lock since added traction is generally not needed. The axle parts of the vehicles equipped with the locking differential are interchangeable with those equipped with the conventional differential, except for the case assembly.

Conman · Post by **Conman** » Mon Jan 20, 2003 2:10 pm

That's how a G80 "Locking Rear" works. IIRC, an "LSD" unit is very similar but you need wheel spin(torque) to get the LSD to activate, while it appears the G80 Locker is almost always engaged no matter what the wheel speed is.

So the G80 Locker is a Limited Locker that acts similar to a LSD Limited Slip Unit. A true Locker is 100% locked and slips very very little.

BTW, Isuzu calls it's LSD a G80 also but it's not a Locking rear like the factory model.

Jim · Post by **Jim** » Mon Jan 20, 2003 5:46 pm

My G80 feels exactly like all the LSDs I have ever driven. The parts man at my dealer said GM doesn't recommend the limited slip additive but he said to use it so I did. My locker is smooth & quiet but I still have that breaking loose power-slide feeling in the wet. Which leads me to believe the clutch packs have friction even though they aren't locked.

Conman · Post by **Conman** » Mon Jan 20, 2003 9:20 pm

Jim wrote:My G80 feels exactly like all the LSDs I have ever driven. The parts man at my dealer said GM doesn't recommend the limited slip additive but he said to use it so I did. My locker is smooth & quiet but I still have that breaking loose power-slide feeling in the wet. Which leads me to believe the clutch packs have friction even though they aren't locked.

When I first had the truck, I def. could feel the locking rear kick in all the time. at 3k, I had the rear fluid changed and they added the additive(well atleast they charged me). At first, I thought the additive ruined my locking cause it felt it was not working. But after some "testing", It was working, just much more smoother, less notchy feeling. So def. the additive did not hurt it, but actually made it smoother. Will see how it last.

Cheers,

Con

quickbiker · Post by **quickbiker** » Tue Jan 21, 2003 3:55 am

I wonder if these are really Eaton lockers, aka Gov Loc?

Post by **HenryJ** » Thu Nov 01, 2007 4:41 am

BADs Crew wrote:Locking Differential Demo

Post by **HenryJ** » Fri Oct 03, 2008 5:04 pm

Another good differential video: How the automobile differential allows a vehicle to turn a corner while keeping the wheels from skidding.
circa 1937. An oldie but goodie.

F9K9 · Post by **F9K9** » Fri Oct 03, 2008 6:19 pm

HenryJ wrote:Another good differential video:.........................

I don't want to know how you found that one but, it is an outstanding video