Rear End ID...no really! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Itnkrman · 02-16-2014, 11:50 PM

Here's a few pics of my rear end...uh, trucks rear end...and I'd like a few expert's advise on manufacture, type and where to locate the ID numbers to help identify/confirm same. I believe it to be an Eaton rear-end based on what I've seen but I'd like some confirmation, additional info, etc...

**Captainfab** · 02-17-2014, 02:15 AM

That is an Eaton HO32 under a '60-'62. It will most likely have 3.90 gears unless you are one of the lucky few to have the 3.38 gears.

Itnkrman · 02-17-2014, 11:11 PM

So is there any way to definitively tell which gear ratio it is without cracking it open?

72freak · 02-17-2014, 11:28 PM

raise it, spin the wheels and count the rotation of the drive shaft. Then look it up on the net. It should get you close.

BLK65K10 · 02-18-2014, 12:40 AM

The 1/2 ton is stamped on the right front carrier flange. It will be two letters followed by 4 numbers. The letters designate the ratio and the numbers are the day and month made. If yours is original it should MA,MB,MC,MD,ME,MF,MG. which are all 3.90.

**GMCNUT** · 09-16-2018, 10:07 AM

Quote:

Originally Posted by BLK65K10

The 1/2 ton is stamped on the right front carrier flange. It will be two letters followed by 4 numbers. The letters designate the ratio and the numbers are the day and month made. If yours is original it should MA,MB,MC,MD,ME,MF,MG. which are all 3.90.

Hey Lyle! I am so glad you wrote this - I’ve been needing to know how to tell if one has the rarer 3:38 gears vs standard 3:90’s. Can you tell me what the letters have to be for a 3:38? Or better yet, do you have a rear ended with 3:38’s in it?
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Brad54 · 02-18-2014, 02:18 AM

Buy a new gasket for the rear cover, remove the cover, change the fluid, count the teeth on the ring gear and the pinion gear, do the math, reseal the rear cover and top it off with fresh fluid. Chances are that fluid is long overdue for a change.

-Brad

TJ's Chevy · 02-18-2014, 12:09 PM

Not to hog up the thread, Hey guys...I have the GM 12 bolt under my 66..Is that 4.11 or was a 3.73 ratio optional???

**Captainfab** · 02-19-2014, 01:24 AM

This is what I always suggest also when a guy wants to know what gears are in his rear end.

Quote:

Originally Posted by Brad54

Buy a new gasket for the rear cover, remove the cover, change the fluid, count the teeth on the ring gear and the pinion gear, do the math, reseal the rear cover and top it off with fresh fluid. Chances are that fluid is long overdue for a change.

-Brad

**rideblue00** · 02-18-2014, 12:51 PM

3.73 was usually the norm, most spids specified the 4.11, on 66's that is

Itnkrman · 02-18-2014, 11:51 PM

Thanks all for the advise...I'll get it cleaned up this weekend and see what the numbers are and go from there.

02-16-2014, 11:50 PM	#1
Itnkrman Registered User Join Date: Aug 2011 Location: China Spring, Tx. Posts: 19	Rear End ID...no really! Here's a few pics of my rear end...uh, trucks rear end...and I'd like a few expert's advise on manufacture, type and where to locate the ID numbers to help identify/confirm same. I believe it to be an Eaton rear-end based on what I've seen but I'd like some confirmation, additional info, etc... Attached Images

02-17-2014, 02:15 AM	#2
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Rear End ID...no really! That is an Eaton HO32 under a '60-'62. It will most likely have 3.90 gears unless you are one of the lucky few to have the 3.38 gears. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

02-17-2014, 11:11 PM	#3
Itnkrman Registered User Join Date: Aug 2011 Location: China Spring, Tx. Posts: 19	Re: Rear End ID...no really! So is there any way to definitively tell which gear ratio it is without cracking it open?

02-17-2014, 11:28 PM	#4
72freak Rottenwood Garage Member Join Date: May 2005 Location: Marietta, Georgia Posts: 4,321	Re: Rear End ID...no really! raise it, spin the wheels and count the rotation of the drive shaft. Then look it up on the net. It should get you close. __________________ 2004 Chevrolet Suburban C1500 2001 Chevrolet 2500HD Crew 6.0 1999 Harley Davidson Electra Glide 1972 Chevrolet C-20 Custom Camper "Dump Truck" 1972 Chevrolet C-20 Suburban "Big Green" 1969 Chevrolet C-50 Wedge Hauler "Leonidis" 1966 C-10 2x4 short fleet 327 4 speed "Race Truck" 1952 Plymouth Cranbrook "Rican" (my grandfathers) 1931 Ford Model A Coupe "Black Beauty" 1930 Ford Model A truck "Club Cab" 4x4 Rottenwood Garage and Speed Shop.....where everything must be racy! *It's not just a hobby..It's a LIFESTYLE!!!* Thanks for nothing Barrett-Jackson You cant fix stupid or teach accountability! Time wasters, looky Lous and tire kickers are everywhere!

02-18-2014, 12:40 AM	#5
BLK65K10 Registered User Join Date: Mar 2012 Location: Bonners Ferry Idaho Posts: 1,024	Re: Rear End ID...no really! The 1/2 ton is stamped on the right front carrier flange. It will be two letters followed by 4 numbers. The letters designate the ratio and the numbers are the day and month made. If yours is original it should MA,MB,MC,MD,ME,MF,MG. which are all 3.90.

02-18-2014, 02:18 AM	#7
Brad54 Registered User Join Date: Aug 2006 Location: Athens, Georgia Posts: 1,458	Re: Rear End ID...no really! Buy a new gasket for the rear cover, remove the cover, change the fluid, count the teeth on the ring gear and the pinion gear, do the math, reseal the rear cover and top it off with fresh fluid. Chances are that fluid is long overdue for a change. -Brad __________________ '61 Suburban daily driver: off the road due to 180-pound 8-pt buck! '62 K-10 long-step project '61 C30 Camper, aka "Valdez" There's no cool like Old School

02-18-2014, 12:09 PM	#8
TJ's Chevy Registered User Join Date: Mar 2013 Location: Southern Oregon Posts: 10,384	Re: Rear End ID...no really! Not to hog up the thread, Hey guys...I have the GM 12 bolt under my 66..Is that 4.11 or was a 3.73 ratio optional??? __________________ 1966 Chevy C10 "Project Two Tone" http://67-72chevytrucks.com/vboard/s...d.php?t=596643 1964 GMC "Crustine" semi-build:http://67-72chevytrucks.com/vboard/s...d.php?t=665056 My youtube channel. Username "Military Chevy": https://www.youtube.com/channel/UC_h...fzpcUXyK_5-uiw

02-18-2014, 12:51 PM	#10
rideblue00 Senior Member Join Date: Feb 2010 Location: Lambertville, MI Posts: 1,866	Re: Rear End ID...no really! 3.73 was usually the norm, most spids specified the 4.11, on 66's that is

02-18-2014, 11:51 PM	#11
Itnkrman Registered User Join Date: Aug 2011 Location: China Spring, Tx. Posts: 19	Re: Rear End ID...no really! Thanks all for the advise...I'll get it cleaned up this weekend and see what the numbers are and go from there.



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