G80 replacement

[Fifty]

I’m debating a gear change on my 2015i GMC Yukon XL.

I have the 3.43 gears I believe.

We don’t do much freeway driving… however when I changed my 3.42 geared colorado with the 8l45 (same gear ratio as our 8l90) to a 4.56 gear set…. I actually got 2mpg better on the freeway.
It made 6,7 and 8th gear usable at speed.

Anyways, I’m considering a numerically higher gearing for the our XL. Since I’ll be doing a little more off-roading and I’ll be towing an off-road trailer.

Since I’m doing that I’m considering a new diff… I was initially going to go with an Eaton e-locker. I’ve had two vehicles now with them and like them way better than the arb I had before.

However I do like have an lsd… getting both tires gripping on the street with out having to flip a switch is nice.

I am considering a mechanical lsd/locker like a Truetrac…. These vehicles are heavy enough back there to tame them.

Anyone have any experience with anything other than the g80?

 

[number9]

I’ve had the G80 in vehicles since 1999. Never had an issue with one, they just work when they’re needed.

Having said that, those vehicles weren’t “wheeled”, just general driving and getting in wet grass, dirt, or mud when it had to be done.

Recently got a ‘22 F-250 with the E-locker and I don’t like it. It works fine and all, but I just don’t like having to engage / disengage it when it’s needed. I’d MUCH prefer to have the G80 in the Furd.

 

[Rygrego]

3.08 is standard. 3.42 was optional. Check your RPOs for ratios. G80 stands for locking diff not ratio. If you have a GU4 it is a 3.08.

 

[OR VietVet]

3.08 is standard. 3.42 was optional. Check your RPOs for ratios. G80 stands for locking diff not ratio. If you have a GU4 it is a 3.08.

You beat me. The G80 is the locker and not the gear ratio.

To answer the original question, I like my G80 in my z71 and the only other locker I have had experience with is a very harsh Detroit Locker in my purpose built rock crawler years ago. When that thing locked in, you knew it.

 

[Fifty]

Yea. I just couldn’t remember which gear ratio it is exactly.
The g80 is not so bad. And when they work they are fine. Ours goes into full lock up but only when there is wheel spin.

The problem with that is when off-road you don’t want multiple rotations to induce a lock up. For one that’s a lot of stress but also it can keep you or dig you into more trouble.

Hence the selectable locker. And as number9 pointed out, the down side to selectable lockers is when you need both tire traction in unforeseen events… it’s not good.

Hence the trutrac… they require less wheel spin to engage so less negatives than the g80… and also have full locking ability.

The question is: does the suburban or Yukon xl have enough girth to make the trutrac style diff smooth?

 

[OR VietVet]

I have had friends that swear by Tru-Trac lockers for everyday and light off roading. If I remember right, they are made by Detroit Locker. I don't think you can go wrong with Tru-Trac but it also depends on how hard you are on your equipment.

 

[mrpeterclark]

The shops tell me the Eaton Truetrac does nor work in reverse? Is that true? I'm about to re-gear mine for 35s and the shops don't like G80s, say the Eaton doesn't work in reverse, and the Yukon Grizzly is loud and harsh for daily driving... I like an auto locker, but maybe an E locker is better? Not sure what fits the 10 bolt though. I don't want to mess with air.

 

[Doubeleive]

The shops tell me the Eaton Truetrac does nor work in reverse? Is that true? I'm about to re-gear mine for 35s and the shops don't like G80s, say the Eaton doesn't work in reverse, and the Yukon Grizzly is loud and harsh for daily driving... I like an auto locker, but maybe an E locker is better? Not sure what fits the 10 bolt though. I don't want to mess with air.

I have never heard of that, could be true but seems like it would have came up before, also seems like that kind of detail would be noted by every single re-seller I would reach out to eaton to confirm/deny

 

[duke90]

The shops tell me the Eaton Truetrac does nor work in reverse? Is that true? I'm about to re-gear mine for 35s and the shops don't like G80s, say the Eaton doesn't work in reverse, and the Yukon Grizzly is loud and harsh for daily driving... I like an auto locker, but maybe an E locker is better? Not sure what fits the 10 bolt though. I don't want to mess with air.

I think the ARB RD222 is the one needed for the 2015+ yukons/suburbans if wanting to replace the G80, but I will call ARB on Monday to confirm.

 

[Marky Dissod]

I’m debating a gear change on my 2015i GMC Yukon XL.
I have the 3.42 gears I believe.

We don’t do much freeway driving ... however when I changed my 3.42 geared colorado with the 8l45 (same gear ratio as our 8l90) to a 4.56 gear set ... I actually got 2mpg better on the freeway.
It made 6th, 7th and 8th gear usable at speed.

Anyways, I’m considering a numerically higher gearing for the our XL.
Since I’ll be doing a little more off-roading and I’ll be towing an off-road trailer.

If you have the 6L80E, 3.73 works well with it in SUVs.