Diff lock

[khaledsamy36]

Hello every one , I know that GM has an automatic diff lock , how can I know if my car ( 2017 Sierra 1500 SLT z71 ) is equipped with it or not , my other car is f150 which has an actual button to activate the diff lock .

Thanks

 

 

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[2003 SSEi]

if your truck was equipped with one from the factory, look in your lower glove box door, you will see a listing of all the Regular Production options your equipped with

 

your looking for the Code "G80"

 

if you see G80 listed then you have a automatic locking rear differential

[kickass audio]

As mentioned look for the G80 code in the glovebox but if someone added a locker after the truck was built you could either jack up the rear end and put it in gear with traction control and stabilitrak disabled and see if when you speed up a little both wheels will lock and unlock to try and keep them at the same speed. Another method is to have the rear end jacked up and spin one tire by hand as fast as you can and then suddenly stop it and try to turn it backwards. If you have a locker when you go to spin the tire the opposite direction from what you started at you will hear a loud clunk and the wheel on the other side that you were not spinning will begin to change motion immediately once it locks up.

[US Dashworks]

You could always put one tire on pavement and the opposite tire on dirt and........ you see where im going with this correct?

[L86 All Terrain]

You will know you have a G80 when it feels and sounds like it is exploding when it locks. 

[Supreme Pizza]

Call the dealer, and give them your VIN#. They should be able to tell you if you have a locking diff. They can use that number to access the build sheet for the vehicle. If you contact GM directly, they will email you a copy of the build sheet. 

[khaledsamy36]

Thank you all , yes it has the G80 .
Being automatic diff lock ( from your experience ) is it as effective as the manual one in F150 ?


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[btj_z71]

30 minutes ago, khaledsamy36 said:

Thank you all , yes it has the G80 .
Being automatic diff lock ( from your experience ) is it as effective as the manual one in F150 ?


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Better! Dont have to think about it, it just kicks in automatically.  I think its something like when the difference between the two wheels is 200rpm, I can't remember exactly, itll lock it up.  Get in the dirt and try it out! 

[khaledsamy36]

Better! Dont have to think about it, it just kicks in automatically.  I think its something like when the difference between the two wheels is 200rpm, I can't remember exactly, itll lock it up.  Get in the dirt and try it out!  [emoji4]

I will , thank you


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[Snowcamo]

I think it's when the opposite wheel reaches more the 10mph, then they both are locked together and spin at the same rate.

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[L86 All Terrain]

2 hours ago, btj_z71 said:

Better! Dont have to think about it, it just kicks in automatically.  I think its something like when the difference between the two wheels is 200rpm, I can't remember exactly, itll lock it up.  Get in the dirt and try it out! 

Correct, the one wheel needs a 200rpm difference before it locks up, and it wants to unlock as soon as you let off the gas. I find on ice or snow it sounds and feels really bad when it is locking/unlocking if you are spinning a tire. It will sounds and feel clunky, where the old Posi-tracks did not. I am really surprised people are breaking these things from improper use, but Eaton is easily one of the best driveline component manufacturers on the planet. If you spun a tire at 200rpm and reached down for the diff lock switch in a manual diff lock truck, you would blow your diff apart. I have 6-way diff locks in my class 8's, all on air switches. Personally, I would much prefer if I could control when the diff was locked vs. open but I totally see why GM does it this way for unexperienced end users. Otherwise people would have the front and rear locked up in the summer and try to go through a drive thru, then bitch at GM for using poor quality components.. 

[SierraHD17]

A Detroit locker fixes the G80s problems quite nicely.  Not really an option however for the 9.5 and 9.76 inch 12 bolts unfortunately.

[rah7777777]

Are the G80 units made by Eaton? 

 

I installed an Eaton Detroit TrueTrac in my '02 Silverado and it worked GREAT!

I LOVED that diff! No more 1 wheel spin on rainy days or especially pulling out of a parking lot onto a busy road when concrete wasn't completely dry or clean. TrueTrac is a work of pure art in my book!

[SierraHD17]

The G80 is an eaton unit.  Same silly design since 1973 and they just keep plugging along with it.  Maybe they can apply "fifty years of the gov bomb" on the trucks for 2023 lol.

 

The Trutrac is a helical gear driven limited slip designed for road racing.  I use one in the front of my 1990 Jimmy because it allows you to turn corners like an open diff.  Doesn't do much in a straight line but it's better than an open carrier.  

[rah7777777]

I disagree...  I never had an issue straight line, both tires always spun together. And coming from my open diff, I promise I noticed haha. 

It would turn with no clicks or pops or issues at all, but as soon as you punched it, both tires would spin together. (Truck had no traction control system)

Only issue was how easy it was for the truck to get sideways in the rain versus just sitting there with the RR tire just spinning. But I was that idiot who slung the ass end of the truck around every corner when it was raining just because it was so easy to do with the TrueTrac. I'm a TrueTrac fan for sure!