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Rear differential

LsSwapDaWorld

By LsSwapDaWorld
in Ask A GM Technician

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LsSwapDaWorld New Member

LsSwapDaWorld

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I’ve got this 06 Chevy Silverado single cab I bought it was a v6 to v8 swap 

I’m looking to find out if my differential was swapped the truck currently has caliper breaks in the back and I’ve seen a couple people mention they have drums on there 06 what could I do to find out if my differential was swapped ?

Jsdirt Senior Enthusiast

Jsdirt

Posted
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Really difficult to tell. I have drums on my '07 Silverado 1500, but I've seen many others of the same year with disc. Just depends on the option package, and what system GM decided to use in production that day.

 

Whether it's swapped or not doesn't really matter as long as the gearing is correct for a 4x4, and the brakes work as designed. Most of the time the identical rear end assembly is used whether the vehicle is a V6 or 6.0 or larger V8.

 

The "G" prefix RPO code will tell you what the gearing was from the factory. That's about it.

Jsdirt Senior Enthusiast

Jsdirt

Posted
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How can you say that without seeing it?

newdude Senior Enthusiast

newdude

Posted
Posted (edited)
8 hours ago, LsSwapDaWorld said:

I’ve got this 06 Chevy Silverado single cab I bought it was a v6 to v8 swap 

I’m looking to find out if my differential was swapped the truck currently has caliper breaks in the back and I’ve seen a couple people mention they have drums on there 06 what could I do to find out if my differential was swapped ?

 

 

If you have an 06 regular cab with rear discs, its been swapped.  Drums came out in 2005, regular cabs didn't get rear discs again until 2014.

 

The only other possibility is if that truck isn't an 06 LOL (perhaps an 04 with an 06 face?)

 

52 minutes ago, Jsdirt said:

How can you say that without seeing it?

 

 

Because its a regular cab, and becuase 2005 GM switched to rear drum.  No regular cabs from 05-13 got factory rear discs. 

 

2007-2013 on the -900 chassis, drums were also standard, and only certain configs got rear discs like Vortec Max and NHT trucks.  

Edited by newdude
LsSwapDaWorld New Member

LsSwapDaWorld

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37 minutes ago, newdude said:

 

 

If you have an 06 regular cab with rear discs, its been swapped.  Drums came out in 2005, regular cabs didn't get rear discs again until 2014.

 

The only other possibility is if that truck isn't an 06 LOL (perhaps an 04 with an 06 face?)

 

 

 

Because its a regular cab, and becuase 2005 GM switched to rear drum.  No regular cabs from 05-13 got factory rear discs. 

 

2007-2013 on the -900 chassis, drums were also standard, and only certain configs got rear discs like Vortec Max and NHT trucks.  

Truck is a 06 says it on title but how can I find out what gears it has ?

JimCost2014 Senior Enthusiast

JimCost2014

Posted
Posted
37 minutes ago, LsSwapDaWorld said:

Truck is a 06 says it on title but how can I find out what gears it has ?

Look at the RPO sticker in the glove box.

 

The codes will start with GU or GT for the rear end ratio.

  • Like 1
shakenfake Senior Enthusiast

shakenfake

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Since it has been swapped you would just have to do some calculating with RPMs.

You would hope they would put the same gear ratio back in but that's just a hope.

Silverado4x4 Senior Enthusiast

Silverado4x4

Posted
Posted

No calculating needed, if you can't find the info on the ratio jack the back of the truck up both wheels off the ground mark the driveshaft with tape or chalk mark the tire at 12 o'clock position spin the tire 1 turn back to the 12 o'clock position count how many times the driveshaft went around if it went around 3.5 times then it's a 3.42 3 3/4 times it's a 3.73 and so on.

richard wysong Senior Enthusiast

richard wysong

Posted
Posted

or you could look for a tag on the cover or pull the cover and its stamped on the ring gear

  • Like 1
newdude Senior Enthusiast

newdude

Posted
Posted (edited)
3 hours ago, LsSwapDaWorld said:

Truck is a 06 says it on title but how can I find out what gears it has ?

 

 

Gotcha.

 

Yea what others said, the jack the wheel method that Silverado4x4 posted would work the fastest.  Glovebox might not match unless they used the same gear ratio that the truck was built with.

 

Or if the stampings are still legible in the right axle tube.  Data stamp should be above the right shock mount, top of the tube.  First set of #s is the gear ratio.  

 

In the glovebox, in the "G"s.  Gu4 = 3.08, GU5 = 3.23, GU6 = 3.42, GT4 = 3.73, GT5 = 4.10.

 

Factory 2wd V6 that year, 3.23 was  it.  4x4 got 3.73.

Edited by newdude
LsSwapDaWorld New Member

LsSwapDaWorld

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On 7/8/2022 at 11:22 AM, shakenfake said:

Since it has been swapped you would just have to do some calculating with RPMs.

You would hope they would put the same gear ratio back in but that's just a hope.

I don’t think there stock gears because when I went to go get tuned my tuner was saying my cluster rpm’s weren’t reading right unless that’s a cluster problem not sure 

shakenfake Senior Enthusiast

shakenfake

Posted
Posted (edited)

Well tires could also throw off RPMs as well. You need to put on stock tires and then go drive at a set speed, use your phone to get you to be at 60 MPH and NOT the speedometer. Only then will you know what gear ratio you have

Edited by shakenfake
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