1998 K2500 limit slip or locking?

[Schurkey]

The shorter version of the video posted above.

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The pawl can be "flimsy" because no vehicle torque is transmitted through it. All it does is cause the ramp-plate to apply pressure to the clutch-packs.

The governor prevents engagement of the ramp plates above a certain speed. However, if the ramp plates are engaged below the governed speed, as long as torque is applied they stay engaged. When torque is released, the ramp plates release, and won't re-engage until the speed drops below the governed speed.

 

[RichLo]

A Detroit locker has a much more "violent ' engagement, especially under throttle on a turn. The clutches are there so that when the vehicle makes a turn one wheel can spin faster than the other without the wheel hop that you get with a Detroit locker in a turning situation under moderate power on a dry road condition.

A real locker isn’t violent when it engages because it’s already engaged. The only time the locker clicks is when you go around a corner when not on the gas. If you floor it you get 50% to each tire until you let off even around a corner.

Your both right, Sean is describing how a full carrier Detroit acts. And Evil Uncle is describing how a lunchbox locker acts. I have owned both and I will never use another lunchbox locker in anything! While the full detroit locker in my dually is fantastic, it stays locked 99% of the time. The only time it unlocks is when I am turning tight into a parking space with 0% throttle on a hot day after a long drive.

 

[Cadillacmak]

Straight from Eaton. See attached.

 

[JDGMC]

I can remember running into the GM nomenclature mess years ago. Purchased a firebird formula 350 with my first real job - scoring some major cash though an incentive program at IBM. I beat the crap out of it - adolesence. Destroyed the diff (G80). Decided to rebuild or replace it. I bought it from the dealer based on a part number I looked up. It turned out to be the wrong one. I finally came to the conclusion that GM generalized the G80 RPO for cars and trucks in their documents as "G80 AXLE,REAR,POSITRACTION,LIMITED SLIP". In the end a truck G80 is likely a Gov-Lok and a car G80 is limited slip. I recall a service bulletin not recommending friction modifiers for G80 trucks when servicing a chatter complaint - which GM attributed to contaminated gear oil. The concern with friction modifiers was the potential for lockup engagement delay. I did rebuild the one I destroyed. Had to borrow some special tools from a shop owner who was a friend of the family. I also rebuilt a G80 on a truck as well. As mentioned above it's not for repetitive burnouts, but it does what it's suppose to when used for it's intended purpose. It actually may be a tad better than a LS when you need traction from a stand still. Most G80's on the older trucks are just abused, not maintained (contaminated oil) or the wrong oil. I agree, it's not a clutch system that drives the wheels, it's more like padding for the sudden engagement (pressure) which is very quick. To much slip (wrong oil) or not enough slip (worn clutches) will definitely bang the hell out of the diff be it engaging at higher wheel RPM or no padding. Oh the the memories..

 

[Sean Buick 76]

You are correct the car G-80 is a limited slip and the truck version is a locker. They really should have named them differently as it causes a lot of confusion especially when looking for which fluid to use.

 

[GoToGuy]

As I mentioned before, RPO codes are not specific. But if your building trucks and it says use diff's G80, its a G80 specific for trucks. Not a G80 for a Camaro. RPO tells you what you have , but parts book tells you what part it is.

 

[Pinger]

While the full detroit locker in my dually is fantastic, it stays locked 99% of the time. The only time it unlocks is when I am turning tight into a parking space with 0% throttle on a hot day after a long drive.

If I've understood Detroit Lockers correctly, in the unlocking situation you describe, the outer wheel's speed over-runs the inner wheel's speed - yes?
If so, what stops them both over-running (like free wheels) in any off-throttle over-run situation (pre-load?)?

 

[Pinger]

OP - you might want to check the axial end play at the wheels. Wear in the G80's clutch packs create play there. Worse for some reason or other on the passenger side.

FWIW, I'm in the clutches-do-the-locking camp. Everything else is to engage the mechanism that loads the clutches - or prevent that happening.

 

[RichLo]

If I've understood Detroit Lockers correctly, in the unlocking situation you describe, the outer wheel's speed over-runs the inner wheel's speed - yes?
If so, what stops them both over-running (like free wheels) in any off-throttle over-run situation (pre-load?)?

This situation is exactly why I hate the 'lunchbox locker' design. That left me turning out of a gas station in the middle of winter with no forward or reverse, I gassed it turning and the one side was already disengaged then the other side somehow also disengaged and it just spun. I had to put it in park to stop it then neutral to let it spin slow enough to re-engage one of the axles so I could get out of traffic. That happened a few times in winter with cold fluid but the other times were in empty parking lots where I could take my time getting it to re-engage.

The real Detroit is just a better design, I think it uses springs to keep the teeth engaged 99% of the time and I'm sure the machining tolerances are a lot better where it wont allow both sides to pop loose like the cheap lunchbox did to me. The lunchbox just uses a wedge design on the cross-pin where the torque will force the center two sections out to engage the axles.

Edit, if anybody wants to go cheap with a drop-in unit to replace the spiders or G80, go full spool, dont mess around with the cheap lockers or clutch style limited slip. You'll hardly notice the full spool and it'll be 100% reliable.

 

[454cid]

I've never driven one, but I'm pretty sure a spool is not what a person should be driving on the street. A spool is usually competition hardware and would get old very fast on the road.