How to determine if rear-end is Posi? - Chevrolet Forum - Chevy Enthusiasts Forums

How to determine if rear-end is Posi?


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Join Date: Jul 2007
Posts: 14

October 19th, 2008, 1:38 PM   #1  
How to determine if rear-end is Posi?

Hey Guys,

I'm about to go help the sis buy a used Tahoe/Yukon (2004-2006). She'll be doing some trailering with her horse so I want to be sure the truck has a Posi rear end.

How do I determine if it does have Posi, and how can I determine the rear-end gear ratio?

Thanks,


 
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October 19th, 2008, 3:02 PM   #2  
RE: How to determine if rear-end is Posi?

check the RPO or build codes in the glove box for one of these:
G80 9027 P AXLE POSITRACTION LIMITED SLIP
G81 9028 P AXLE POSITRACTION FULL LOCKING DIFFERENTIAL, ELECTRONIC, DRIVER SELECT


EDIT
and if you want to know what every one of those build codes means...

http://aplsweb.com/Topics/TopicPix/RPO.pdf

second EDIT the rear end ratios

GU2 8525 P RAX M AXLE REAR 2.73 RATIO
GU4 8527 P RAX M AXLE REAR 3.08 RATIO
GU5 8528 P RAX M AXLE REAR 3.23 RATIO
GU6 8529 P RAX M AXLE REAR 3.42 RATIO
GU7 8530 P RAX M AXLE REAR 2.77 RATIO
GU8 8531 P RAX M AXLE REAR 3.90 RATIO
GU9 8532 P FAX M AXLE FRONT 3.91 RATIO

 
Join Date: Jul 2007
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October 19th, 2008, 3:37 PM   #3  
RE: How to determine if rear-end is Posi?

in2,

Do they make the Tahoe/Yukon in an open rear end? If so, what is the build code for the open rear-end? I noticed that the two options you listed above are both Posi rear-ends.


Thanks,
CMOS

 
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October 19th, 2008, 3:50 PM   #4  
RE: How to determine if rear-end is Posi?

I can't answer the open diff question maybe one of the other guru's Shawnvw or Shark can...
as for the 2 listed one is electroniclly controlled I would assume a part of the driver selected traction control or "StbiliTrak" and the other is the GM standard locker...


If I were to guess the G80 is probably the open

 
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October 19th, 2008, 10:23 PM   #5  
RE: How to determine if rear-end is Posi?

My 2007 RPO sheet lists the G80 as Differential, heavy-duty locking rear. No G81 is listed.

 
Join Date: Nov 2006
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October 20th, 2008, 1:27 PM   #6  
RE: How to determine if rear-end is Posi?

The G81 I dont know, The only thing GM has with a selectable locker or electric locker is hummer. the G80 is what you looking for, although for pulling a trailor is not a huge helper, its helps more when taking off, in a boat lauch or mud or off camber stuff. It basically lokcs your rear whe none side starts slipping, kinda making it a posi for a bit.

Open diff is what Ford and Dodge and Jeep and those guys run, or 'limited slip' diffs.

The G80 is NOT open. It is when not being used, BUT soon as wheel spin is there it locks both tires, the others (ford nd Dodge)DO NOT. they use cluth packs...

If you want an open diff just get one with no G80 code.....

 
Join Date: Jul 2007
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October 24th, 2008, 3:41 PM   #7  
RE: How to determine if rear-end is Posi?

Thanks guys,

The G80 functionality is what I want.

CMOS

 
Join Date: Jan 2007
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October 27th, 2008, 10:07 PM   #8  
RE: How to determine if rear-end is Posi?

Watch this video to see how the Eaton G80 handles slippage better than anything else

http://www.youtube.com/watch?v=p8nAbg5suFw

 
Join Date: Jul 2007
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October 28th, 2008, 5:45 PM   #9  
RE: How to determine if rear-end is Posi?

ORIGINAL: RonH

Watch this video to see how the Eaton G80 handles slippage better than anything else

http://www.youtube.com/watch?v=p8nAbg5suFw
I've looked at the Eaton web site before when I bought a Tru-Trac for one of my Fords. I never did see anything labeled as a G80. Is this a designation ONLY for GM? Meaning could someone buy a "G80" carrier for a Ford, etc.?

CMOS

 
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October 31st, 2008, 4:52 PM   #10  
RE: How to determine if rear-end is Posi?

take it off road! if it gets stuck with one spinning in the front, and one spinning in the back, its an open diff; just make sure you have a Jeep handy to pull you out

Go somewhere like here:

http://www.facebook.com/photo.php?pi...50&l=2b598

lol

http://www.facebook.com/album.php?ai...;id=1019051350

 
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