G80 possible issue

[gooffeyguy]

Redline 75w90 gear oil has modifier already added into it also

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[iamdub]

That's the thing... it's not a limited slip differential so a friction modifier is not required and not recommended.

The LSD additive actually causes problems for the G80 due to it causing slipping in the clutch packs of the locker.

That is why I didn't buy/add anything else to it.

There is even a TSB telling dealers not to add the additive to the G80.

I had to look that up and just ran across something I've never realized- The RPO "G80" is used for "Limited Slip Differential" as well as "Mechanical Locking Differential". Apparently, one got the friction modifier and the other didn't.

Learnt sumpin' new.

 

[swathdiver]

Well Ken, if your Mobil One bottle says LS on it, it has the friction modifier in it already.

 

[kbuskill]

I had to look that up and just ran across something I've never realized- The RPO "G80" is used for "Limited Slip Differential" as well as "Mechanical Locking Differential". Apparently, one got the friction modifier and the other didn't.

Learnt sumpin' new.

Yep G80 in the car applications is a LSD... G80 in a truck application is a locker.

 

[kbuskill]

Well Ken, if your Mobil One bottle says LS on it, it has the friction modifier in it already.

I will have to look at the bottle... I think I still have one.

I am certain it does though. Mobil 1's site shows the 75w90 as LS.

 

[swathdiver]

G80 in a truck application is a locker.

It's both a locker and a limited slip. According to GM, they've been using this since the 1980s.

 

[thompsoj22]

It's the first time I've had a "problem" with it.

The funny thing is I just changed the fluid in the stupid thing before we took our trip at Christmas.

Drained the old fluid out and looked it over... no real metal on the magnet... just normal stuff... didn't even smell bad like they normally do.

I refilled with Mobil 1 75w90 without any LS modifiers or anything.

Any way... I will try to do some more testing I guess. Hopefully it holds together.

I hate beating on a truck with 230k miles on it. Unfortunately I can't think of any other way to get consistent results for comparisons. And for tuning purposes it requires the WOT logs.

No offense but if your gonna play race car's with a 6k lb boat at least use some water to get the tires hot/sticky so you dont have spin on launch. your "limited slip" was designed for the occasional ice/snow/mud loss of traction and allmost requires a slippery surface to survive when it engages. the locking mechanisim might last for a couple more dry pavement burnouts and than there go's your headers in a diff replacement!. Forget the racetrack BS and do timed 10 mph rollon starts, it is more accurate in determining how your performance upgrades will get you up to speed on a freeway onramp as opposed to "launching" from a dead stop. No disrespect intended here as i see many of your posts and you know what your doing! no additive req in gov lock diff's so your fluid is irrelevant, it is just your gov lock screaming "im about to grenade"!

 

[kbuskill]

No offense but if your gonna play race car's with a 6k lb boat at least use some water to get the tires hot/sticky so you dont have spin on launch. your "limited slip" was designed for the occasional ice/snow/mud loss of traction and allmost requires a slippery surface to survive when it engages. the locking mechanisim might last for a couple more dry pavement burnouts and than there go's your headers in a diff replacement!. Forget the racetrack BS and do timed 10 mph rollon starts, it is more accurate in determining how your performance upgrades will get you up to speed on a freeway onramp as opposed to "launching" from a dead stop. No disrespect intended here as i see many of your posts and you know what your doing! no additive req in gov lock diff's so your fluid is irrelevant, it is just your gov lock screaming "im about to grenade"!

No offense taken. I agree, the 10mph roll is probably a better idea and definitely easier on the equipment.

 

[Ilikemtb999]

It's both a locker and a limited slip. According to GM, they've been using this since the 1980s.

Yep, and the one in my blazer is actually beefy and works well even off-road. 14 bolt axle is much larger.