I have the build sheet for this truck, but alas - no G80 locker. Can someone please tell me what other rear end options were available for a Z71 4x4 of this year?
Surely GM would not build a 4x4 truck without at least a LSD rear end?! Even my '92 Nissan 4x4 had a limited slip rear axle. Please tell me this is not an open differential!
BTW, I have not tried jacking up the rear and turning one wheel to see what happens - yet.
Can anyone shed light on this issue?
Regards,
Ken aka N4UOO
Update:
Rolled RR tire forward (trans. in neutral), LR tire rolls backward. What does this mean with regard to original question?
The LR tire, can you stop it while rolling the RR forward. Sounds like a Limited Slip
I would "assume" so (geeze - I do know what trouble that word can cause). Did not actually try. Was performing this "test" by myself.
When trying this, I would suddenly change directions on the one I was moving by hand. When I did so, the other side would slow to a stop then change directions. Either way, the opposite side was definitely moving in the opposite direction from the one I was physically rotating.
That means open diff, since the drive shaft isn't turning the spider gears are. G80 was the only factory option of a locking differential, they didn't offer an LSD.
If there is not G80 code, it does not likely have a GovLoc in it. It was not standard then and standard today only with very few models. Myself I am not a fan of it for my usage (watch the peanut gallery pipe in). I have been stuck good twice in last 15 years and both times LSD would not have made any difference at all because all four tires where mostly spining anyway. The reason I am not fond of it is because it makes vehicle more prone to fishtale on ice and I run a few plow trucks and have for many years and directional control is VERY important. Contray to poular belief, a open diff sends the same amount of torque to both wheels, no more, no less as it can do nothing else. A LSD can send more torque to one axle than the other.
----------------- TheSnoMan.com
The G80 is a LSD that they call a "locker" but a true locker do not use friction clutches to lock up like G80 does,(calling it a locker is a great sales promo/gimic) it is mechanical and cannot slip unless something breaks while a G80 will slip when its torque limit is reached and if reach a lot for any period od time it will toast and not longer be a LSD as many offroads have found out the hard way over the years.
----------------- TheSnoMan.com
Not this again, its only an LSD in your head, everyone else knows the difference. Yes it may have a upper limit where it breaks loose to prevent damage but that is not how an LSD works, when the g80 is engaged it is locked, when a LSD engaged is still allows slip, its like comparing a manual transmission clutch with a torque converter.
The G80 RPO is for the locking diff option.
I dont know what the hell Snoball is rambling about (who the hell ever does) but this is how it is described by GM word for word:
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1998 Chevrolet/Geo Chevy C Pickup - 2WD Locking Differential Description and OperationThe locking differential consists of the following components:
The optional locking differential (RPO G80) enhances the traction capability of the rear axle by combining the characteristics of a limited-slip differential and the ability of the axle shafts to "lock" together when uneven traction surfaces exist. The differential accomplishes this in 2 ways. First by having a series of clutch plates at each side of the differential case to limit the amount of slippage between each wheel. Second, by using a mechanical locking mechanism to stop the rotation of the right differential side gear, or the left differential side gear on the 10.5 inch axle, in order to transfer the rotating torque of the wheel without traction to the wheel with traction. Each of these functions occur under different conditions. Limited-Slip Function
Under normal conditions, when the differential is not locked, a small amount of limited-slip action occurs. The gear separating force developed in the right-hand (left-hand side on 10.5 inch axle) clutch pack is primarily responsible for this.
The operation of how the limited-slip function of the unit works can be explained when the vehicle makes a right-hand turn. Since the left wheel travels farther than the right wheel, it must rotate faster than the ring gear and differential case assembly. This results in the left axle and left side gear rotating faster than the differential case. The faster rotation of the left-side gear causes the pinion gears to rotate on the pinion shaft. This causes the right-side gear to rotate slower than the differential case.
Although the side gear spreading force produced by the pinion gears compresses the clutch packs, primarily the right side, the friction between the tires and the road surface is sufficient to overcome the friction of the clutch packs. This prevents the side gears from being held to the differential case. Locking Function
Locking action occurs through the use of some special parts:
When the wheel-to-wheel speed difference is 100 RPM or more, the flyweights of the governor will fling out and one of them will contact an edge of the latching bracket. This happens because the left cam side gear and cam plate are rotating at a speed different, either slower or faster, than that of the ring gear and differential case assembly. The cam plate has teeth on its outer diameter surface in mesh with teeth on the shaft of the governor.
As the side gear rotates at a speed different than that of the differential case, the shaft of the governor rotates with enough speed to force the flyweights outward against spring tension. One of the flyweights catches its edge on the closest edge of the latching bracket, which is stationary in the differential case. This latching process triggers a chain of events.
When the governor latches, it stops rotating. A small friction clutch inside the governor allows rotation, with resistance, of the governor shaft while one flyweight is held to the differential case through the latching bracket. The purpose of the governor's latching action is to slow the rotation of the cam plate as compared to the cam side gear. This will cause the cam plate to move out of its detent position.
The cam plate normally is held in its detent position by a small wave spring and detent humps resting in matching notches of the cam side gear. At this point, the ramps of the cam plate ride up on the ramps of the cam side gear, and the cam plate compresses the left clutch pack with a self-energizing action.
As the left clutch pack is compressed, it pushes the cam plate and cam side gear slightly toward the right side of the differential case. This movement of the cam side gear pushes the thrust block which compresses the right-hand side gear clutch pack.
At this point, the force of the self-energizing clutches and the side gear separating force combine to hold the side gears to the differential case in the locking stage.
The entire locking process occurs in less than 1 second. The process works with either the left or right wheel spinning, due to the design of the governor and cam mechanism. A torque reversal of any kind will unlatch the governor, causing the cam plate to ride back down to its detent position. Cornering or deceleration during a transmission shift will cause a torque reversal of this type. The differential unit returns to its limited-slip function.
The self-energizing process would not occur if it were not for the action of one of the left clutch discs. This energizing disc provides the holding force of the ramping action to occur. It is the only disc which is splined to the cam plate itself. The other splined discs fit on the cam side gear.
If the rotating speed of the ring gear and differential case assembly is high enough, the latching bracket will pivot due to centrifugal force. This will move the flyweights so that no locking is permitted. During vehicle driving, this happens at approximately 32 km/h (20 mph) and continues at faster speeds.
When comparing the effectiveness of the locking differential, in terms of percent-of-grade capability to open and limited-slip units, the locking differential has nearly 3 times the potential of the limited- slip unit under the same conditions. Locking Differential Torque-Limiting Disc
The locking differential design was modified in mid-1986 to include a load-limiting feature to reduce the chance of breaking an axle shaft under abusive driving conditions. The number of tangs on the energizing disc in the left-hand clutch pack was reduced allowing these tangs to shear in the event of a high-torque engagement of the differential locking mechanism.
At the time of failure of the load-limiting disc, there will be a loud bang in the rear axle and the differential will operate as a standard differential with some limited-slip action of the clutch packs at low torques.
The service procedure, when the disc tangs shear, involves replacing the left-hand clutch plates and the wave spring. It is also necessary to examine the axle shafts for twisting because at high torques it is possible to no only shear the load-limiting disc, but to also twist the axle shafts.
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The Snoball Defense System.
Care to explain "all four tires were mostly spinning" I thought you were a fan of open dif's.
Why am I not surprised that you don't use a ls on the rear. I'm trying to think of who else I know that prefer's a open dif on a 4X4 for snow plowing. If you get the snow plow prep, I believe it comes with the ls. Not as a part of the pkg but on the truck.
I guess when I broke my g80 and had to buy two little gears to fix it I must have had mega clutches in it otherwise it would have slipped
You just do not get it do you??? Lockers DO NOT uses fricton clutches to lock, they use mechanical locks that CANNOT slip. The G80 can and will if enough torque is applied and that is easy to do with oversized tires. Eaton uses a cam to preload engagement a bit to make it appear to be a locker but it is not and also it blocks operation above 20 MPH oe so so above that it is basicallt a open diff with a little bit a LSD from oil shearing in clutches. Also a classic LSD do basically work the same as they all have their break limit and some even increase preload and tighten up even more under torque (like dana PowerLoc LSD) The G80 is a locker in name only and is going to be phased out in future and replaced with a more conventional LSD design.
----------------- TheSnoMan.com
He said it was in neutral, the drive shaft was turning. Put the transmission in park or in first if it's a stick, and try again.
Al
You don't get it, clutches can not slip, just like the clutch in a manual transmission. You can't make up your own definition for something just because you don't agree with it. The G80 does not slip when operating, therefore it is not a limited slip. Note slip is the operative word, limited slip does slip some, g80 does not.
I have to disagree on this one. My G-80 with right tire in mud (deep mud) left on road surface. It started spinning the right wheel, then it clunked in and pulled out using only the left tire that was on road surface. If it weren't for the truck weighing over 8,000 lbs. and having a 12,000 + lbs. trailer fully loaded while this happened... (that's over 20,000 lbs.) If that wasn't locked then I better go to Church and thank the guy upstairs for making it get me out of that mess...
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