Can anyone ID my rear diff? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rick0312 · 03-11-2008, 03:42 AM

Limited slip? What type?...Thanks

**john** · 03-11-2008, 04:33 AM

From what I can see, it looks like an open Eaton.

rick0312 · 03-11-2008, 05:59 AM

it's a 12 bolt cover.

rick0312 · 03-11-2008, 07:19 AM

hand written number on ring gear looks to be 2355. i divided this number and got 4.11 gears? These gears were stock on the 1/2 ton.

Longhorn Man · 03-11-2008, 07:26 AM

that gear could be had as an option, or standard if the overdrive tranny was requested.

slammed1 · 03-12-2008, 11:48 AM

I have yet to see a number like "2355" be used to determine gear ratios.

Most gears sets have a number like 41-11 which equals a 3.73........41 ring gear teeth divided by 11 pinion teeth. The numbers are there just have to be found. If you cant find them look at you ringgear and lace a chalk or grease pencil mark on one tooth then count them,then reach inside best you can and mark a pinion tooth so that you can count those.

The old method of raising a wheel or two off the ground really only applies to Posi type rear diffs where both rear tires will spin equally.........I know many many many have done the spin one wheel and watch driveshaft but a "open" style rear diff will have spider and side gears turning also while one wheel is off the ground giving false info.

slammed1 · 03-12-2008, 11:51 AM

Also with such a thin ring gear I can almost bet your pinion has 10 or more teeth which will probably equal out to be a 3.73 or less,as in maybe closer to 3.08............most highway gears will have a thin ringgear with a large diameter pinion where as non highway(performance gears) gears will have smaller diameter pinions with 10 teeth or less and thicker ring gears.

rick0312 · 03-14-2008, 06:57 AM

thanks slammed! I'll count them.

rick0312 · 03-14-2008, 07:49 AM

you were right slammed...41 teeth on the ring gear and 11 on the pinion=3.73.thanks again.
rick

slammed1 · 03-14-2008, 08:08 AM

No problem,and I think Im the only one with a 72 with 3.08s.

03-11-2008, 03:42 AM	#1
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Can anyone ID my rear diff? Limited slip? What type?...Thanks Attached Images

03-11-2008, 04:33 AM	#2
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Can anyone ID my rear diff? From what I can see, it looks like an open Eaton. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

03-11-2008, 05:59 AM	#3
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Can anyone ID my rear diff? it's a 12 bolt cover.

03-11-2008, 07:19 AM	#4
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Can anyone ID my rear diff? hand written number on ring gear looks to be 2355. i divided this number and got 4.11 gears? These gears were stock on the 1/2 ton.

03-11-2008, 07:26 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: Can anyone ID my rear diff? that gear could be had as an option, or standard if the overdrive tranny was requested.

03-12-2008, 11:48 AM	#6
slammed1 1972 Chevrolet SWB Join Date: Jan 2008 Location: FT Smith AR Posts: 512	Re: Can anyone ID my rear diff? I have yet to see a number like "2355" be used to determine gear ratios. Most gears sets have a number like 41-11 which equals a 3.73........41 ring gear teeth divided by 11 pinion teeth. The numbers are there just have to be found. If you cant find them look at you ringgear and lace a chalk or grease pencil mark on one tooth then count them,then reach inside best you can and mark a pinion tooth so that you can count those. The old method of raising a wheel or two off the ground really only applies to Posi type rear diffs where both rear tires will spin equally.........I know many many many have done the spin one wheel and watch driveshaft but a "open" style rear diff will have spider and side gears turning also while one wheel is off the ground giving false info. __________________ My New thread with pics (not my build thread yet.) http://67-72chevytrucks.com/vboard/s...46#post2573646 1972 Chevrolet 1/2 ton short wide bed,68 frt clip Project. 1980 Camaro Inherited when father passed,68K Miles 2003 Ford Mach1 FUN as Hell!! 2002 Dodge Ram 5-8 slam Rolling BillBoard (Gone not forgot) 2004 Dodge Ram HEMI 10" lifted on 37's and 2wd.

03-12-2008, 11:51 AM	#7
slammed1 1972 Chevrolet SWB Join Date: Jan 2008 Location: FT Smith AR Posts: 512	Re: Can anyone ID my rear diff? Also with such a thin ring gear I can almost bet your pinion has 10 or more teeth which will probably equal out to be a 3.73 or less,as in maybe closer to 3.08............most highway gears will have a thin ringgear with a large diameter pinion where as non highway(performance gears) gears will have smaller diameter pinions with 10 teeth or less and thicker ring gears. __________________ My New thread with pics (not my build thread yet.) http://67-72chevytrucks.com/vboard/s...46#post2573646 1972 Chevrolet 1/2 ton short wide bed,68 frt clip Project. 1980 Camaro Inherited when father passed,68K Miles 2003 Ford Mach1 FUN as Hell!! 2002 Dodge Ram 5-8 slam Rolling BillBoard (Gone not forgot) 2004 Dodge Ram HEMI 10" lifted on 37's and 2wd.

03-14-2008, 06:57 AM	#8
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Can anyone ID my rear diff? thanks slammed! I'll count them.

03-14-2008, 07:49 AM	#9
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Can anyone ID my rear diff? you were right slammed...41 teeth on the ring gear and 11 on the pinion=3.73.thanks again. rick Last edited by rick0312; 03-14-2008 at 07:50 AM.

03-14-2008, 08:08 AM	#10
slammed1 1972 Chevrolet SWB Join Date: Jan 2008 Location: FT Smith AR Posts: 512	Re: Can anyone ID my rear diff? No problem,and I think Im the only one with a 72 with 3.08s. __________________ My New thread with pics (not my build thread yet.) http://67-72chevytrucks.com/vboard/s...46#post2573646 1972 Chevrolet 1/2 ton short wide bed,68 frt clip Project. 1980 Camaro Inherited when father passed,68K Miles 2003 Ford Mach1 FUN as Hell!! 2002 Dodge Ram 5-8 slam Rolling BillBoard (Gone not forgot) 2004 Dodge Ram HEMI 10" lifted on 37's and 2wd.



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