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oneillt

How Do I Know My Truck Has A Locking Diff?

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Hey guys, quick question.

New truck is an 04' GMC z71, and I heard that some z71's can come through the line without the locking diff. I heard the RPO code for the locking diff is g80, but then I also read in a post that it is possible to have this code and not have the locker because it is the same code for a limited slip axle? I ran my vin into the rpo code/rarity site and it spit this back at me

"G80AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)"

Does this mean I do not have the locker, and just have regular limited slip?

 

*edit* I know i can just go find an icy patch to figure this out, but I'm not gunna have the truck for another week.

Edited by oneillt

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If you have a limited slip differential instead of the locking type, both wheels will rotate in the same direction if you jack up the truck by the rear differential and spin one rear wheel by hand (vehicle in neutral). If you have a locking differential, the wheels will rotate in opposite directions, as this differential acts as an open differential when not locked.

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If it has limited slip it is not a factory option. The only factory option is the G80 locking rear differential

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They do not put limited slip axles in trucks

 

A G80 in a truck is a Eaton locker.

 

In 2004 G80 was not standard equipment, if you wanted it you had to pay extra to get it and it was not part of the Z71 option. Later models GM did package with the option but not in 2004.

 

If you have G80, it will show on the label in the glove box along with all the options on the truck. If G80 is not there, you got the standard open differential.

 

People get confused because they assume an option description is the same across all models and that is often not the case. G80 means something different depending on the vehicle it is installed in.

 

G80 - G80AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80) is the description for only in cars

 

G80 Differential, heavy-duty automatic locking rear is the description for trucks

 

here is a official list of GM options from the GM car lines. Notice what they call G80 for each..

 

for 2010 GM trucks list of options

G80 Differential, heavy-duty automatic locking rear

GAT All-Terrain Package

GT4 Rear axle, 3.73 ratio

GU4 Rear axle, 3.08 ratio

GU5 Rear axle, 3.23 ratio

GU6 Rear axle, 3.42 ratio

 

for 2010 Camaro

G80 Differential, limited slip

GM3 Axle, 3.45 ratio

GW6 Axle, 3.27 ratio

JL9 Brakes, 4-wheel antilock, 4-wheel disc

 

for 2010 Cadillac CTS sedan, sport wagon, CTV-V

G80 Differential, limited slip

J55 Brakes, performance 4-wheel antilock, 4-wheel disc

J56 Brakes, Brembo

J77 Brake, electronic parking

JF5 Pedals, metal

 

As you can see from the lists, a limited slip axle is a performance axle which serves little use in a truck

 

Folks who get RPO printouts from online lookups get the "limited slip" text and think they don't have a locker. Those are programed wrong...

 

I wonder how many CTV-V and Camaro owners think they have a locker because they are looking at an option list for trucks?

Edited by elcamino

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The only truck to get a limited slip was the Quadrasteer and it was a G86. The G80 in a truck as has been said will be a locking diff.

 

Now. Starting in 2004 The Z71 INCLUDED the G80 locking diff. It was not a part of the Z71 but a part of the off road package required by the Z71. Before 2004 it was a stand alone option.

 

It would be listed like this in the dealer RPO code book..

 

scan0007-1.jpg

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Hey guys, quick question.

New truck is an 04' GMC z71, and I heard that some z71's can come through the line without the locking diff. I heard the RPO code for the locking diff is g80, but then I also read in a post that it is possible to have this code and not have the locker because it is the same code for a limited slip axle? I ran my vin into the rpo code/rarity site and it spit this back at me

"G80AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80)"

Does this mean I do not have the locker, and just have regular limited slip?

 

*edit* I know i can just go find an icy patch to figure this out, but I'm not gunna have the truck for another week.

 

Just check your Glove Box RPO List, and if one of the Codes reads G80, then Congratulations, You have an Eaton Locking Rear Differential!

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If you have the vin number go here and check.

http://www.compnine.com/vid.php

This is where people get the idea they have a limited slip differential. I have seen it come back as limited slip so this site in not reliable. Matter of fact is shows my CTS as a DTS so there are bugs in that lookup. It also comes back with the wrong paint color.

 

A while back I had one fella come in the shop for gear lube and wanted an additive for his limited slip. When I told him the truck did not have a limited slip he pulled out print-out from this online site or another just like it that said he had a Limited Slip Differential, not a locker. It was wrong! If it tells you your truck has a G80 limited slip its lying to you.

Edited by elcamino

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If you have the vin number go here and check.

http://www.compnine.com/vid.php

This is where people get the idea they have a limited slip differential. I have seen it come back as limited slip so this site in not reliable. Matter of fact is shows my CTS as a DTS so there are bugs in that lookup. It also comes back with the wrong paint color.

 

A while back I had one fella come in the shop for gear lube and wanted an additive for his limited slip. When I told him the truck did not have a limited slip he pulled out print-out from this online site or another just like it that said he had a Limited Slip Differential, not a locker. It was wrong! If it tells you your truck has a G80 limited slip its lying to you.

 

 

 

That site also has my truck listed as being a White truck.

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I'm sorry I was just trying to help.

 

Didn't mean it was bad, just take what ever it says with a grain of salt. I got the dealer to print out a build sheet for me because I was trying to figure out why the website listed my truck as being white. I wanted to make sure something hadn't gotten mixed up.

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Easiest way to get info on your rear end is to look in your glovebox on the sticker on the 'door' (for lack of a better word). If in those tiny little letters it reads G80 you have a G80. If not, you do not.

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Hello, I have a 2005 rwd Colorado LS. I was excited about learning about the Eaton G80 locking differential while doing a little truck research. I will be in the market in the not too distant future and would love to avoid the extra expense of a 4x4. As was mentioned, i looked in the glove box and was very surprised to see a G80. I live on a hill and my truck is terrible in winter weather. I live in the Southeast so it does not hamper me too badly. I would like a truck that would perform better. It looks like already have the G80 and it is not the answer for me. Is there anything in particular that I need to do for this to be engaged or is there a relatively easy way for me to check to see if the locking rear diff. is working? I am not a hard core truck user at all. I went up the hill in my backyard with a pingpong table and that's as off road as it gets for me. Daily commuter and weekend warrior. Love the practicality for hardware store, garden center trips, furniture buying. recycling / dump trips. I greatly dislike my truck's performance in the snow. I tried a suretrax (vinyl water bag for weight) and it did not really seem to help. Any thoughts or recommendations would be appreciated. Thanks

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I like to turn off TCS and see what happens lol.

 

Easier way would be to go in a low traction area and lose grip and see what happens. You can "usually" feel when they kick in. On my 01 Sierra I can feel it kick in and out but on my 11 Silverado you don't even realize it's happening. It ONLY kicks in the locker when there is tire spin. Under normal conditions it acts exactly like an open diff.

 

I love the lockers myself. I used 4wd only a handful of times last year. Couple that with them intense Michelin tires and you can go through 12 inches of snow in 2wd like it's nothing. Completely amazed at the difference coming off the 99-02 SilvySierra.

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They do not put limited slip axles in trucks

 

A G80 in a truck is a Eaton locker.

 

In 2004 G80 was not standard equipment, if you wanted it you had to pay extra to get it and it was not part of the Z71 option. Later models GM did package with the option but not in 2004.

 

If you have G80, it will show on the label in the glove box along with all the options on the truck. If G80 is not there, you got the standard open differential.

 

People get confused because they assume an option description is the same across all models and that is often not the case. G80 means something different depending on the vehicle it is installed in.

 

G80 - G80AXLE,REAR,POSITRACTION,LIMITED SLIP POSITRACTION L/SLIP R/AXL(G80) is the description for only in cars

 

G80 Differential, heavy-duty automatic locking rear is the description for trucks

 

here is a official list of GM options from the GM car lines. Notice what they call G80 for each..

 

for 2010 GM trucks list of options

G80 Differential, heavy-duty automatic locking rear

GAT All-Terrain Package

GT4 Rear axle, 3.73 ratio

GU4 Rear axle, 3.08 ratio

GU5 Rear axle, 3.23 ratio

GU6 Rear axle, 3.42 ratio

 

for 2010 Camaro

G80 Differential, limited slip

GM3 Axle, 3.45 ratio

GW6 Axle, 3.27 ratio

JL9 Brakes, 4-wheel antilock, 4-wheel disc

 

for 2010 Cadillac CTS sedan, sport wagon, CTV-V

G80 Differential, limited slip

J55 Brakes, performance 4-wheel antilock, 4-wheel disc

J56 Brakes, Brembo

J77 Brake, electronic parking

JF5 Pedals, metal

 

As you can see from the lists, a limited slip axle is a performance axle which serves little use in a truck

 

Folks who get RPO printouts from online lookups get the "limited slip" text and think they don't have a locker. Those are programed wrong...

 

I wonder how many CTV-V and Camaro owners think they have a locker because they are looking at an option list for trucks?

I realize this is a fairly old post but this seems to be the most informative answers I've found so far.

 

My question is this. I have a 2013 silverado 1500 z71 and I was curious about the RPO codes for the truck. I went to a local chevy dealership and asked if they could give me a printout of the codes for my truck and what they meant. I gave them my VIN and they provided the codes.

 

G80 is listed but as a "positrac limited slip." According to the post above, does this mean that the dealer's information is wrong or that they are just using a website as well? Or do I really not have the Eaton lockers?

 

 

Sent from my XT1650 using Tapatalk

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