2014 Yukon XL Denali

[2003DenaliXL]

G80 confirmed...........no additive will be used.

Thanks!

 

[Matthew Jeschke]

The G80 is not a limited slip. It's a locker. It doesn't have the clutches that have to slip on every turn. So it doesn't need the friction modifier because you won't have any clutch chatter.

The G80 acts like an open differential. But when one wheel slips and the difference in wheel speeds exceeds 100 RPM, it locks. Once traction is restored, it unlocks.

This video illustrates the difference between the G80 and a typical limited slip

It has clutches. I took mine apart. They apply first when there is a differential then if differential exceeds a certain value the mechanical locker engages.

Rear Axle G80 Differential Rebuild | offroadTB.com

offroadtb.com

I think synthetic 75w80 includes a friction modifier but cannot seem to confirm. Manual appears to call for 75w80

 

[intheburbs]

It has clutches. I took mine apart. They apply first when there is a differential then if differential exceeds a certain value the mechanical locker engages.

Rear Axle G80 Differential Rebuild | offroadTB.com

offroadtb.com

I think synthetic 75w80 includes a friction modifier but cannot seem to confirm. Manual appears to call for 75w80

Wow, nice gravedigging.

Yes, the G80 has clutches. No they don't apply "first." The G80 is either locked, or it's not. There's no middle ground. When you make a turn in a truck with the G80, the differential acts like an open differential. The clutches only come into play if the G80 locking mechanism is tripped. That is why the G80 does not require friction modifiers in the gear oil.

In a traditional limited-slip differential, every time you turn the clutches have to slip against each other. Without the friction modifier, they'll chatter.