Limited slip differential 20 v 21

[Blueinterceptor]

Are they the same?

mechanical or just electronic

 

[Blueinterceptor]

The limited slip on the 21 is product code g86.

anyone know the code for a 20?

 

[cardude2000]

Are they the same?

mechanical or just electronic

My understanding is the there is no real locker. Even on the Z71. It uses the brakes to limit spin instead of a G80


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[Blueinterceptor]

GMC claims its 21 at4 will be its most capable off road truck yet. It’s got the same g86 lsd. I don’t think it’s as capable as the g80

 

[d0wnShifT]

My sticker on the Z71 i just picked up states there's a mechanical LSD inside.

 

[Blueinterceptor]

My sticker on the Z71 i just picked up states there's a mechanical LSD inside.

yes a g86. For the past 20 years it’s been a g80 hd automatic locking diff

 

[cardude2000]

My sticker on the Z71 i just picked up states there's a mechanical LSD inside.

I believe it’s a LSD but not a “true” mechanical locker in that it can’t lock in a 50/50 power split to both wheels. The G86 has been used for years for more street prone vehicles and lite utes like the Saab 9-7x


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[wjburken]

Some manufacturers are even going to open rear diffs and relying strictly on using the brakes to put power to the other side.

 

[DWSmoot]

Time frame starting at 7:00 minutes.

 

[Blueinterceptor]

That video is what prompted this thread.
I’ve been looking into if a g80 can replace it.
I’m wondering if the guy didn’t spin the wheels fast enough. The other rear wheel should have done something but it clearly did not
I went to a dealership and had the parts manager look up the axle for a 21 suburban. G86 was not listed but a g80 positraction was.

same dealer looked up the rear end by vin. It is a G86 limited slip

 

[thecodeman]

Playing around on the GMC website for the 2021, there are two options on the AT4 (I, too, looked after watching this video and found it ironic that the Z71 didnt offer a mechanical limited slip)

On the AT4 4x4 Yukon, standard feature is:

• Mechanical limited-slip rear differential
  • When the differential senses a significant difference in wheel speed, it locks to turn both rear wheels in unison for added traction
  • Redistributes power to the drive wheels, providing you with more control
  • Helps your vehicle power through the tough terrain by keeping the rear wheels moving together

Optionally, you can choose:

"Electronic Limited-Slip Differential (eLSD)

• Uses vehicle sensors and driver inputs to determine the optimum amount of engagement for driving conditions
• Optimizes torque split between the rear wheels that provide enhanced stability and maximum traction
• May require additional optional equipment"

When you check that option:

"Changing Electronic Limited-Slip Differential (eLSD) will also change the following:
Add

• Enhanced Cooling Radiator
• ProGrade Trailering System
• Integrated trailer brake controller
• In-vehicle Trailering App
• Hitch Guidance with Hitch View
• Adaptive Air Ride suspension
• Premium Capability Package with Active Response 4WD
• Trailer Side Blind Zone Alert
• Max Trailering Package

Price Change: $2,260"


*edit* I went back to look at the z71 4x4 Tahoe, and it too reports standard mechanical limited slip

• Mechanical limited-slip rear differential
  • When the differential senses a significant difference in wheel speed, it locks to turn both rear wheels in unison for added traction
  • Redistributes power to the drive wheels, providing you with more control
  • Helps your vehicle power through the tough terrain by keeping the rear wheels moving together

 

[Blueinterceptor]

I happened upon a you tube video that showed a different guy using his mech limited slip.
Apparently the L/S and IRS are made by American axle

The 2021 police version Tahoe describes the L/S as heavy duty mechanical L/S.

 

[swathdiver]

 

[Artem-G]

That looks really cool! I wonder what’s the explanation for the first video posted here where it was utterly helpless. A preproduction sample glitch?..

 

[swathdiver]

That looks really cool! I wonder what’s the explanation for the first video posted here where it was utterly helpless. A preproduction sample glitch?..

I think they said that the Yukon has the electronic limited slip and the Tahoe does not.

 

[Artem-G]

I think they said that the Yukon has the electronic limited slip and the Tahoe does not.

Interesting, but even more confusing! Double checking the configurator, it says that Mechanical LSD is standard on all trims of Tahoe and Yukon, and Electronic LSD is an option that comes with the Premium Offroad Capability package.

So apparently this mechanical LSD is as good as an open differential?..

Even more confusingly, the Z71 in the original video has an air suspension. Doesn't that come with eLSD?

 

[swathdiver]

Interesting, but even more confusing! Double checking the configurator, it says that Mechanical LSD is standard on all trims of Tahoe and Yukon, and Electronic LSD is an option that comes with the Premium Offroad Capability package.

So apparently this mechanical LSD is as good as an open differential?..

Even more confusingly, the Z71 in the original video has an air suspension. Doesn't that come with eLSD?

Artem, don't know for sure, still Greek to me too. In time, we'll digest it. Saw on an SLT "build your own" this morning that it came with a mechanical ls and there was no option for the electric, seems to be reserved for the AT4.

It's also possible that the demonstrator vehicle, the Tahoe that TFL used was supposed to have the electric limited slip or maybe the programming wasn't active, or who knows! LOL

 

[Blueinterceptor]

The video I posted showed the mech ls working

 

[Artem-G]

So… I drove my stock 22”-wheeled Denali on some gravel/stony roads today and I am happy to confirm the mechanical LSD is nowhere as useless as the first video here suggested. I only drove in 2H and still didn’t manage to get any wheel slippage — even when starting from standstill on a steep, uneven gravel surface that gave my 2017 Lincoln Navigator trouble despite decent tires and 4H mode.

 

[Blueinterceptor]

I’m wondering if the first vehicles failure was a result of a fear of the driver that he’d damage one of only a few vehicles available for show. I don’t think that the lsd will be as strong as the g80 but I’m hopeful that it will be good enough.