The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 99-06 GMT800 Chevy and GMC Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-24-2021, 10:34 AM   #1
67sss
Registered User
 
67sss's Avatar
 
Join Date: Nov 2002
Location: Mt. Vernon, WA..
Posts: 2,322
2004 GMC 3500 rear end size question

Pulled my Vin number and decoded the options. I know I have a 3:73 rear-end ratio. How do I tell what size rear-end I have? 9.5, 10.5 or 11.5? I'm getting ready to replace the parking brake pads and a axle seal. Tia
67sss is offline   Reply With Quote
Old 09-24-2021, 03:46 PM   #2
hatzie
Moderator
 
hatzie's Avatar
 
Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,911
Re: 2004 GMC 3500 rear end size question

Won't be a 9.5 in a 3500 You can tell right away if you have one of these by looking. The other two axles are full floating so the hubs extend out from the wheel with the bolts holding in the axle shaft. The 9.5 is a C Clip axle like the 10 bolt and 12bolt.

LQ4 gasoline will have the 10.5

The dirtymax will have the 11.5

Not sure about the 8.1L They came with the Allison so it might have an 11.5 out back.
__________________
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
hatzie is offline   Reply With Quote
Old 10-03-2021, 07:03 PM   #3
Richard
Senior Member
 
Join Date: Dec 1999
Location: Southern California
Posts: 2,664
Re: 2004 GMC 3500 rear end size question

An easy tell for an 11.5 is that the pinion will have a damper on it. Looks like a harmonic balancer. I know the 11.5 came in 2500HD's I have seen. My swap rear end is from one. I would wager an 11.5.
__________________
Richard
1972 K10 Custom Deluxe SWB Fleetside
My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

Last edited by Richard; 10-03-2021 at 07:11 PM.
Richard is offline   Reply With Quote
Old 10-04-2021, 11:01 AM   #4
95 S_Trucker
Registered User
 
95 S_Trucker's Avatar
 
Join Date: Oct 2009
Location: .
Posts: 2,178
Re: 2004 GMC 3500 rear end size question

You have an 11.5". The only way it could be a 10.5 is if the truck was a SRW with a 6.0. But the 6.0 trucks had 4.10 ratio. So, since your truck has 3.73, we can tell you have an 8.1 or 6.6. So you have an 11.5".
95 S_Trucker is offline   Reply With Quote
Old 10-25-2021, 06:13 PM   #5
67sss
Registered User
 
67sss's Avatar
 
Join Date: Nov 2002
Location: Mt. Vernon, WA..
Posts: 2,322
Re: 2004 GMC 3500 rear end size question

Thanks for the help! 11.5" it is. Just replaced inner and outer bearings, seals, parking brake pads and changed rear diff fluid. I seem to have a "bounce" coming from somewhere. Shocks are new all the way around. Wondering if the carrier bearing is starting to go out? The best way to describe the "bounce" is after going over a rough road, it seems like the truck suspension feels like I'm driving over washboard. Probably will replace the u-joints and the carrier bearing to see if that helps. Any other suggestions are appreciated.
67sss is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:14 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com