GM RPO code GT5 G80

[Writefast]

So in doing some research I learned that I have 4:11 gears and a positrac limited slip dif. That is literally the extent of my knowledge about any of this. As someone who wants to be able to competently use this truck in som light Florida off-road, what does any of that actually mean? As a Mustang guy 4:10s meant quick off the line, high rpm at highway speed. I think limited slip means both rears spin “sometimes” at once? And positrack just means whatever the guy I was talking to meant at that time. Weird question but what do I know about my truck knowing that it has a 4:11 rear and positrac?

 

[TollKeeper]

G80 is a Eaton Auto Locking Differential. Not a Posi-Limited Slip.

I would love to have the GT5 gears... Hell I would be happy with GT4 3.73 Gears... But alas, I have GU6 3.42

 

[Marky Dissod]

So in doing some research I learned that I have 4.11:1 gears and a positrac limited slip dif.
That is literally the extent of my knowledge about any of this.

GT5 = 4.10 to 1 - NOT 4 to 11.
G80 means different things to different vehicles. For GMT vehicles, don't think GM provided a limited slip differential.
G80 for GMT = an open differential that locks if one wheel spins quicker (slower?) than the other by more than 100RpM.
Over 20-something MpH, you don't have a G80, just an open differential.

... what do I know about my truck knowing that it has a 4.10:1 rear and positrac?

Your 4.10:1 Yukon'd be quicker off the line than a similar one with 3.73, and quicker by moreso than one with 3.42.
It's also better-equipped to tow considerably more.
You also likely get slightly better city MpG, possibly at the cost of a highway MpG or two, depending on how leadfoooted you are.
(You lucky bastaducci).

You don't have a positrac, though. You have the cheapest differential enhancement GM was willing to put in your rear axle.
When one rear tire is in the air, it should be able to put enough power down to the grounded tire to get / keep you moving, provided you don't gun the everlovin schidt out of it (they used to be called Gov-Bombs for a reason; plenty of videos of people blowing them up).

 

[TollKeeper]

For GMT vehicles, don't think GM provided a limited slip differential.

They did, but not in the Full Size.. They had a G86 Limited Slip offered in the smaller GMT360 (Trailblazer) if you had the SS option.

 

[Writefast]

So tows well, and shifted mileage if you’re not a lead foot, which I am. lol.

 

[Marky Dissod]

For whatever it's worth, I remember being excessively leadfooted with a Caprice wagon that had a 2.56 axle, which I hated GOTTDAMNT!
Long story short, upgrading that axle from 2.56 to 3.42 made me quite a bit less of a leadfoot, and much happier.

If your Yukon had 3.73 or 3.42, you might be even more of a leadfoot.

 

[strutaeng]

So in doing some research I learned that I have 4:11 gears and a positrac limited slip dif. That is literally the extent of my knowledge about any of this. As someone who wants to be able to competently use this truck in som light Florida off-road, what does any of that actually mean? As a Mustang guy 4:10s meant quick off the line, high rpm at highway speed. I think limited slip means both rears spin “sometimes” at once? And positrack just means whatever the guy I was talking to meant at that time. Weird question but what do I know about my truck knowing that it has a 4:11 rear and positrac?

Interesting. I'm assuming you have a 4L60/65e?

G80 10 bolt are actually pretty decent. Guys that blow them up are either running huge tires or going pretty aggressive stuff, none of which the differential was designed to do.

I've got the G80 bolt on my 99 Silverado ECSB 2wd and it's actually gotten me out of trouble more than a few times.

Take it out to some mild trails to play around so you can figure out how it works and the feel of it engaging. There's a decent "jolt" when it engages which is normal.

 

[swathdiver]

So in doing some research I learned that I have 4:11 gears and a positrac limited slip dif. That is literally the extent of my knowledge about any of this. As someone who wants to be able to competently use this truck in som light Florida off-road, what does any of that actually mean? As a Mustang guy 4:10s meant quick off the line, high rpm at highway speed. I think limited slip means both rears spin “sometimes” at once? And positrack just means whatever the guy I was talking to meant at that time. Weird question but what do I know about my truck knowing that it has a 4:11 rear and positrac?

Take it the track and see how fast off the line she is with those gears, the 60-foot!

Short wheelbase 2007 4x4 Yukon has a 7,700 pound tow rating. As for off-road fun, it will help some over 3.73s if you get into the sticky stuff, especially in 4LO.

 

[RST Dana]

GT5 = 4.10 to 1 - NOT 4 to 11.
G80 means different things to different vehicles. For GMT vehicles, don't think GM provided a limited slip differential.
G80 for GMT = an open differential that locks if one wheel spins quicker (slower?) than the other by more than 100RpM.
Over 20-something MpH, you don't have a G80, just an open differential.

Your 4.10:1 Yukon'd be quicker off the line than a similar one with 3.73, and quicker by moreso than one with 3.42.
It's also better-equipped to tow considerably more.
You also likely get slightly better city MpG, possibly at the cost of a highway MpG or two, depending on how leadfoooted you are.
(You lucky bastaducci).

You don't have a positrac, though. You have the cheapest differential enhancement GM was willing to put in your rear axle.
When one rear tire is in the air, it should be able to put enough power down to the grounded tire to get / keep you moving, provided you don't gun the everlovin schidt out of it (they used to be called Gov-Bombs for a reason; plenty of videos of people blowing them up).

I don’t see where the op indicated “4 to 11”.

 

[Marky Dissod]

I don’t see where the op indicated “4 to 11”.

I have 4:11 gears

The driveshaft does not spin 4x for every 11 spins of the tires; he does not have 4:11.
The driveshaft spins 4.1x for every spin of the tires, he has 4.10 (lucky bastaducci).