Limited Slip diff in 2003 Yukon

Design-Jedi · August 9, 2003

The rear differential in my new 2003 Yukon is supposed to be a locking G80 unit

With both tires off the ground I turn one tire and the other tire rotates in the opposite direction. No GM limited slip I have ever seen would do this only open diffs.

Is it time to pull the rear cover and look or is this already enough to prove I do not have a locking rear diff?

Bish · August 10, 2003

Normal. The unit acts like an open diff until it detects a 200rpm (I think) difference between both wheels when it locks. Mine acts the same way and it definitely has a G80.

Colorado Kid · August 21, 2003

Try your tuning the tire trick again, but spin it as fast as you can . . . blam, it'll lock and they'll both pretty much stop (because each side has the same momentum).

If you don't want to do that much work just stop with one wheel in dirt and romp it. . . if the one in the dirt digs a hole and you just sit there it's open, but if it takes off just about like both wheels were on the hard surface, well then it's a locker.

robsawatsky · August 22, 2003

Many others have confused the limited-slip and locking differentials; 2 different beasts. The G80 RPO is an Eaton locker, which is an open diff until the flyweight governor kicks in at high difference in wheel speeds.

See for product description:

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

Dihappy · August 22, 2003

Save some money and get a better one (ie Eaton or Auburn LSD)

The G80 will also disengage at about 15-20mph

robsawatsky · August 22, 2003

Not sure what you are saying. The G80 is the Eaton locker. Or are you saying get the Eaton LSD?

In any case, lockers are what you want for offroad traction. LSDs are for street, strip or track traction.

Dihappy · August 22, 2003

The LSD that eaton sells is different from the factory offered G80. Eaton sells a better unit as well as Auburn in their Pro Series.

I know of more than one person whos G80 grenaded and personally i hated mine.

The Auburn Pro Series Diff i now have is much better.

Dihappy · August 22, 2003

In any case, lockers are what you want for offroad traction. LSDs are for street, strip or track traction.

True, if you want a real locker, its hard to beat the new Eaton Electrac or a good ole ARB Air Locker. A buddy even has a Detroit in his truck and loves it but youll get big pops sometimes on turns and it may be more difficult to drive in rain than an LSD.

But just cuz the G80 says "locker" dont mean its a real full time locker and the better aftermarket Eatons and Auburns are much better anyway.

frdfandc · August 26, 2003

Just put a spool in it

Tjwong · August 30, 2003

Your G80 option is commonly known around the GM enthusists as the "GOV BOMB" it is known as that because the unit has a governor affair inside of the differential that swings out as differential speed is sensed between the slipping wheels, as speed increases a flyweight swings out to engage the posi unit thus locking the differential.

These units are rather weak and if abused the can come apart. But one good thing about the way it is designed and that is the parts of teh governor and the clutch wearing cone is made of a powdered metal material which even when it breaks up is softer than the gears and spider gears inside the differential The parts being softer will not hurt the gears even if they are being ground up by the gears.

My plans are to replace my 3/4T differential with an aftermarket Eaton unit that is a traditional positraction unit with springs and clutches. I can;t remember the brand name off the top of my head but I beleive it is the Eaton LSD to replace my OEM GM 10.5" rear end. To replace the GM locker unit costs well over $800 dealer cost, it is rediculous what it costs. I was shocked to find this out after a friend wiped on out in his 1T dually messing around at the drag strip. We ended up replacing it with an open differential for a half if its cost. Later we found out that we can get a replacement traditional posi unit from Garys Ring and Pinon for less than the cost of the open diff from GM!

AZ1500 · September 1, 2003

Go with ARB Air Locker

PeterbiltChrome · April 19, 2004

I'm content with my no-slip powertrax locker.... saved $$$ initial cost and IMO it performs better than the G80 diffs in our other pickups.

snoman · May 28, 2004

The rear differential in my new 2003 Yukon is supposed to be a locking G80 unit
With both tires off the ground I turn one tire and the other tire rotates in the opposite direction. No GM limited slip I have ever seen would do this only open diffs.

Is it time to pull the rear cover and look or is this already enough to prove I do not have a locking rear diff?

It is operating correctly, it takes about 200 RPM difference to engage and usually goes in with a bang. The one used in 10 bolt carriers are known for a lack of durability. The ones used in 9.5 inch 14 bolt are somewhat better and the 10.5 inch 14 bolt carrier ones are the best of them durablity wise. Personally, I do not like them because of what can be clunky operation and they do not work above 15 to 20 MPH. I prefer the Eaton LSD (not Gov Lock) or a Truetrac gear LSD.

snoman · May 28, 2004

I'm content with my no-slip powertrax locker.... saved $$$ initial cost and IMO it performs better than the G80 diffs in our other pickups.

These can be too harsh on street on slick pavement and can really suck towing a trailer because it may not unload enough in turns when towing to let one wheel disengage and free wheel around curve. They should be considered a off road item with limited street use.