any way to tell what ratio rear? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**crossy** · 11-23-2015, 10:35 AM

I'm assuming my open end ,6 lug rear is a 4.10 or something? the truck was originally a 6 cyl with 3 speed. anyway to tell w/o opening her up. I know on a posi(that works) you can count the revs, but not on an open diff. thanx , crossy

**PGSigns** · 11-23-2015, 10:58 AM

99% were 3.73. There is a set of numbers stamped into the housing. Best thing to do is just pull the cover and take a look. This lets you know the true ratio and gets some fresh oil in it that most really need.
Jimmy

**crossy** · 11-23-2015, 12:29 PM

passenger side axle tube is where the stampings were on my 73-87's? sound right? haven't really looked at yet, but I don't remember this rear having a cover. it's pumpkin style in 61 right?

jtrichard · 11-23-2015, 01:48 PM

Jack up ONE side,with trans in NEUTRAL turn the wheel and count the turns on the drive shaft cut that number in HALF and you have the ratio .......IF the lifted wheel wont turn or turns very hard then you have a posi

61K10 · 11-23-2015, 01:52 PM

If you have a 61 tk and the rear is org. it has a pumpkin and a rear cover also. the axles have c-clips (y the cover) most were 3.90 gears with the 3 & 4 speed. post up a pic.

**Captainfab** · 11-24-2015, 02:31 AM

Most '60-'62 1/2 tons came with the Eaton HO32/33 and 3.90 gears. The only other gear ratio available is 3.38. Yes they do have a drop out 3rd member but they also have a removable rear cover. I always recommend pulling the cover and having a look. Then bolt the cover back on with a new gasket and fill with some fresh gear oil. The differentials are one of the most neglected parts of a vehicle and yours could more than likely use an oil change.

**crossy** · 11-24-2015, 12:37 PM

Quote:

Originally Posted by Captainfab

. The differentials are one of the most neglected parts of a vehicle and yours could more than likely use an oil change.

NOPE,NOPE, the whole truck was obviously neglected equally.
actually I shall neglect it no longer , but I'm bettin dollars to donuts that no one stocks an Eaton HO32/33 rear gasket. at least it's easy to get to since there is no wood left on the bed floor. LMAO

61K10 · 11-24-2015, 01:08 PM

you can get the gaskets at any auto parts store here on the w/coast. don't know about NJ

11-23-2015, 10:35 AM	#1
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	any way to tell what ratio rear? I'm assuming my open end ,6 lug rear is a 4.10 or something? the truck was originally a 6 cyl with 3 speed. anyway to tell w/o opening her up. I know on a posi(that works) you can count the revs, but not on an open diff. thanx , crossy __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.

11-23-2015, 10:58 AM	#2
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: any way to tell what ratio rear? 99% were 3.73. There is a set of numbers stamped into the housing. Best thing to do is just pull the cover and take a look. This lets you know the true ratio and gets some fresh oil in it that most really need. Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

11-23-2015, 12:29 PM	#3
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	Re: any way to tell what ratio rear? passenger side axle tube is where the stampings were on my 73-87's? sound right? haven't really looked at yet, but I don't remember this rear having a cover. it's pumpkin style in 61 right? __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.

11-23-2015, 01:48 PM	#4
jtrichard Registered User Join Date: Jun 2013 Location: joshua tree ca. Posts: 1,484	Re: any way to tell what ratio rear? Jack up ONE side,with trans in NEUTRAL turn the wheel and count the turns on the drive shaft cut that number in HALF and you have the ratio .......IF the lifted wheel wont turn or turns very hard then you have a posi

11-23-2015, 01:52 PM	#5
61K10 Registered User Join Date: Feb 2012 Location: pleasant valley--placerville ca Posts: 3,039	Re: any way to tell what ratio rear? If you have a 61 tk and the rear is org. it has a pumpkin and a rear cover also. the axles have c-clips (y the cover) most were 3.90 gears with the 3 & 4 speed. post up a pic. __________________ 1961 chevy K10 my build is------------61K10 build

11-24-2015, 02:31 AM	#6
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: any way to tell what ratio rear? Most '60-'62 1/2 tons came with the Eaton HO32/33 and 3.90 gears. The only other gear ratio available is 3.38. Yes they do have a drop out 3rd member but they also have a removable rear cover. I always recommend pulling the cover and having a look. Then bolt the cover back on with a new gasket and fill with some fresh gear oil. The differentials are one of the most neglected parts of a vehicle and yours could more than likely use an oil change. __________________ 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

11-24-2015, 01:08 PM	#8
61K10 Registered User Join Date: Feb 2012 Location: pleasant valley--placerville ca Posts: 3,039	Re: any way to tell what ratio rear? you can get the gaskets at any auto parts store here on the w/coast. don't know about NJ __________________ 1961 chevy K10 my build is------------61K10 build

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