rear diff indentification! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

NewAge1970 · 04-08-2012, 08:53 PM

How do i identify my rear differential without removing the diff cover and looking at it ? 1970 gmc pickup

**special-K** · 04-08-2012, 09:35 PM

1/2t? Do you want to identify the axle or the ratio? The axle could be a Dana44,even a Dana60,or a Corporate 12-bolt. To figure out the ratio you can turn the rear wheel and count the turns with one turn of the driveshaft. A 3.07 is just over 3 turns,3.73 is right about 3 3/4 turns,and a 4.10 is a bit over 4 turns. A 3spd truck would have 3.73 as standard and an automatic truck wold have 3.08s. Other ratios would be optional and listed on the SPID,unless the rear or ratio was changed.

NewAge1970 · 04-09-2012, 09:21 AM

im looking at identifying the differential, to see if it had a limited slip or a open diff. i had a 3spd so i know the ratio. i am just wondering if i have a rebuildable diff or do i need to buy one.

04-08-2012, 08:53 PM	#1
NewAge1970 Registered User Join Date: Oct 2010 Location: Riverton Wyoming Posts: 93	rear diff indentification! How do i identify my rear differential without removing the diff cover and looking at it ? 1970 gmc pickup __________________ "Its better to burn out than it is to rust!" '70 GMC C10 2wd. 2.02 aluminum heads. TH400 trans. 450WHP '04 Nissan 350z DD, Twin Turbo, 600whp, drag beast!

04-08-2012, 09:35 PM	#2
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: rear diff indentification! 1/2t? Do you want to identify the axle or the ratio? The axle could be a Dana44,even a Dana60,or a Corporate 12-bolt. To figure out the ratio you can turn the rear wheel and count the turns with one turn of the driveshaft. A 3.07 is just over 3 turns,3.73 is right about 3 3/4 turns,and a 4.10 is a bit over 4 turns. A 3spd truck would have 3.73 as standard and an automatic truck wold have 3.08s. Other ratios would be optional and listed on the SPID,unless the rear or ratio was changed. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

04-09-2012, 09:21 AM	#3
NewAge1970 Registered User Join Date: Oct 2010 Location: Riverton Wyoming Posts: 93	Re: rear diff indentification! im looking at identifying the differential, to see if it had a limited slip or a open diff. i had a 3spd so i know the ratio. i am just wondering if i have a rebuildable diff or do i need to buy one. __________________ "Its better to burn out than it is to rust!" '70 GMC C10 2wd. 2.02 aluminum heads. TH400 trans. 450WHP '04 Nissan 350z DD, Twin Turbo, 600whp, drag beast!



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