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G80 not unlocking

ashman

ashman

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My 2017 2500hd is keeping the rear tires locked up when I turn.

I pulled the brakes off to confirm that they weren't the issue. It does unlock, but locks really easily.
View attachment 20240814_231832.mp4

Do I need to replace the G80? Will a fluid change help?
 
fluid change should help if oil is old. One tsb I read years ago said to do figure 8's free a sticky LS. Once I needed to do so with 14bff G80 after a long 400 mile trip.
 
Wes Harden said:
fluid change should help if oil is old. One tsb I read years ago said to do figure 8's free a sticky LS. Once I needed to do so with 14bff G80 after a long 400 mile trip.
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The oil looked clean enough to me, but I'd bet it's never been changed. 100k+ miles on the truck.
 
I’ve had to go into many many G80’s and I can tell ya that yours is having flyweight troubles and it will lead to failure.
Individual parts are hard to get but usually by the time those smaller components start to fail it’s a snowball effect.
It may last for a while but start getting ready for a replacement.

The additive that induces slip only helps the clutches but the problem you are experiencing is the reason why your clutches are engaging.
At this point your diff is gonna lock up abruptly and/or constantly on pavement and it’s just not designed to handle that kind of use.
Even though a 10.5” version has a stronger three-pinion design carrier or if it’s the larger 11.5” two-pinion version which helps in distributing the pressure it ain’t gonna do it forever.
 
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You would think it lost a spring on the centrifugal weights or the little catch block (governor).

1723718839862.png
 
Blue85 said:
You would think it lost a spring on the centrifugal weights or the little catch block (governor).

View attachment 483795
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Yes Sir !
And by the time that spring leaves the party the cam & governor are not feeling well and start chuck’n teeth off of each other.
If he could replace those two components before the rest of the diff goes through hell that would work until the they both begin to fail again one day.
Those are the parts that always fail first on G80’s that are not abused by driving styles and/or neglect.

Note: For the OP - if your axle is a 10.5” your diff will not look like the diagram ( it works the same though ) it will be inclosed between two case halves and have a three-pinion cross pin and gears.
If it’s the 11.5” axle it’s just an overgrown version of the 10B G80.
 
It's an 11.5. So basically, I need to replace it. :cry:

Never tried to source a g80 before. Hope it's not too expensive. Ugh
 
ashman said:
It's an 11.5. So basically, I need to replace it. :cry:

Never tried to source a g80 before. Hope it's not too expensive. Ugh
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By ALL means replace it with the Torsen type unit that Dodge used in their AAM 11.5’s.
It is a FAR SUPERIOR differential!

Just my opinion but I’d feel bad if I did not let ya know that there is an better OEM option from AAM that GM was too stubborn to offer because they are hell bent on sticking with the Gov-Bomb.

The Torsen type diff is very effective and durable and strong - it should be the last diff you ever have to buy for that truck and that can not be said about the G80…

Here’s a pic of each 11.5” AAM diffs - all the three pinion sets of internals of the Dodge unit are huge but can’t say the same for the two on the G80.

IMG_9192.png

IMG_9191.png
 
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tarussell said:
By ALL means replace it with the Torsen type unit that Dodge used in their AAM 11.5’s.
It is a FAR SUPERIOR differential!

Just my opinion but I’d feel bad if I did not let ya know that there is an better OEM option from AAM that GM was too stubborn to offer because they are hell bent on sticking with the Gov-Bomb.

The Torsen type diff is very effective and durable and strong - it should be the last diff you ever have to buy for that truck and that can not be said about the G80…
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I'm willing to look into it, but this is just my tow pig, and the g80 lasted 100k+ miles.
Babaganoosh said:
Last time I heard of this the guy swapped a 10.5 into his because it was cheaper.
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Interesting. I would have thought that the ring gear bolt pattern would be different.
 
ashman said:
I'm willing to look into it, but this is just my tow pig, and the g80 lasted 100k+ miles.

Interesting. I would have thought that the ring gear bolt pattern would be different.
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It’s worth looking into the price of each - if it’s close I would think hard about it.
 
ashman said:
I'm willing to look into it, but this is just my tow pig, and the g80 lasted 100k+ miles.

Interesting. I would have thought that the ring gear bolt pattern would be different.
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I think he was talking about the complete axle - the 10.5” diff will not fit it’s an entirely different design.
 
Id find one in a junkyard that's open diff and swap the whole axle, if you don't need a limited slip. Around here whole axles are cheaper than gear setup and install.
 
Id find one in a junkyard that's open diff and swap the whole axle, if you don't need a limited slip. Around here whole axles are cheaper than gear setup and install.
 
Id find one in a junkyard that's open diff and swap the whole axle, if you don't need a limited slip. Around here whole axles are cheaper than gear setup and install.
 
I can do the gear setup and install myself, that isn't an issue, but you may be right. It would still be cheaper to get a full axle most likely.
 
tarussell said:
By ALL means replace it with the Torsen type unit that Dodge used in their AAM 11.5’s.
It is a FAR SUPERIOR differential!

Just my opinion but I’d feel bad if I did not let ya know that there is an better OEM option from AAM that GM was too stubborn to offer because they are hell bent on sticking with the Gov-Bomb.

The Torsen type diff is very effective and durable and strong - it should be the last diff you ever have to buy for that truck and that can not be said about the G80…

Here’s a pic of each 11.5” AAM diffs - all the three pinion sets of internals of the Dodge unit are huge but can’t say the same for the two on the G80.

View attachment 483807

View attachment 483808
Click to expand...

This what you are talking about?
It appears to be way cheaper too...
 
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