Rearend question??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gulfcoast66 · 08-09-2007, 11:41 AM

I have a old question, I have a 72 12 bolt rearend thats on the ground, How can i tell the gear in it. The suburban i yankit from still had the paper card taped to the inside of the glove box door, It said 411 gears but now that im cleaning it up i notice that the rearend has had work done to it somewhere in the past.
What is the simplest way to determen the gear raitio

jchav62 · 08-09-2007, 12:03 PM

You'll have to take off the diff cover and read the numbers stamped on the ring gear. Divide those #'s into eachother...that's your ratio.

Jonboy · 08-09-2007, 12:19 PM

You can also rotate the wheel once and count the number of revolutions of the pinion. Pulling the cover to get the numbers is more "correct", but counting hte revoultions of the pinion will get you close.

gulfcoast66 · 08-09-2007, 12:40 PM

I got the cover off , where are the numbers located at ? what should i be looking for?
Thanks Chris.

1969k10stepside · 08-09-2007, 12:45 PM

On the ring gear in a spot there is a bunch of numbers and there will be some that say 41 11 for example,that being the number of teeth on the ring and pinion

gulfcoast66 · 08-09-2007, 01:18 PM

I really dont know if im reading the correct #'s, but the only #'s that are readable are 3866116 n ? these #'s are stamped on the back side of the ring gear, how do i divide this?

62 short step · 08-09-2007, 01:27 PM

Quote:

Originally Posted by gulfcoast66

I really dont know if im reading the correct #'s, but the only #'s that are readable are 3866116 n ? these #'s are stamped on the back side of the ring gear, how do i divide this?

You can't divide those. Count the teeth on the ring gear write it down, then count the teeth on the pinion gear write it down. Now divide those two #'s that should be your ratio.

killer71 · 08-09-2007, 01:54 PM

Quote:

Originally Posted by 62 short step

You can't divide those. Count the teeth on the ring gear write it down, then count the teeth on the pinion gear write it down. Now divide those two #'s that should be your ratio.

jchav62 · 08-09-2007, 01:24 PM

That's probably the part number or something. The numbers you are looking for should be close to that. Right below if I remember correctly. It should be 4 digits (41 11). Those are the numbers and divide them to get your ratio... 41/11=3.73.

gulfcoast66 · 08-09-2007, 02:05 PM

Thanks alot everyone,I found somemore #'s 3817778 1141 gm 972. So I divided 41 and 11 and 3.72, Im going with 3.73 gears. where can I find a better highway gear, 3.42, at a decent price?

08-09-2007, 11:41 AM	#1
gulfcoast66 64-66 CHEVY JUNKIE Join Date: Apr 2007 Location: Cypress ,Texas Posts: 1,516	Rearend question??? I have a old question, I have a 72 12 bolt rearend thats on the ground, How can i tell the gear in it. The suburban i yankit from still had the paper card taped to the inside of the glove box door, It said 411 gears but now that im cleaning it up i notice that the rearend has had work done to it somewhere in the past. What is the simplest way to determen the gear raitio __________________ 1966 C-10 Fleetside LWB, 350 Lt1 4l60-E 2008 Silverado Crew Cab, 4.8 4l60-E 1998 GMC Yukon 4x4 L-31 Vortec, 4l60-E 2017 GMC Serra 4x4 5.3 Vortec, 4l60-E Do It In A Chevrolet

08-09-2007, 12:03 PM	#2
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: Rearend question??? You'll have to take off the diff cover and read the numbers stamped on the ring gear. Divide those #'s into eachother...that's your ratio. __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4

08-09-2007, 12:19 PM	#3
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: Rearend question??? You can also rotate the wheel once and count the number of revolutions of the pinion. Pulling the cover to get the numbers is more "correct", but counting hte revoultions of the pinion will get you close.

08-09-2007, 12:40 PM	#4
gulfcoast66 64-66 CHEVY JUNKIE Join Date: Apr 2007 Location: Cypress ,Texas Posts: 1,516	Re: Rearend question??? I got the cover off , where are the numbers located at ? what should i be looking for? Thanks Chris. __________________ 1966 C-10 Fleetside LWB, 350 Lt1 4l60-E 2008 Silverado Crew Cab, 4.8 4l60-E 1998 GMC Yukon 4x4 L-31 Vortec, 4l60-E 2017 GMC Serra 4x4 5.3 Vortec, 4l60-E Do It In A Chevrolet

08-09-2007, 12:45 PM	#5
1969k10stepside Registered User Join Date: Mar 2006 Location: USA Posts: 21,019	Re: Rearend question??? On the ring gear in a spot there is a bunch of numbers and there will be some that say 41 11 for example,that being the number of teeth on the ring and pinion

08-09-2007, 01:18 PM	#6
gulfcoast66 64-66 CHEVY JUNKIE Join Date: Apr 2007 Location: Cypress ,Texas Posts: 1,516	Re: Rearend question??? I really dont know if im reading the correct #'s, but the only #'s that are readable are 3866116 n ? these #'s are stamped on the back side of the ring gear, how do i divide this? __________________ 1966 C-10 Fleetside LWB, 350 Lt1 4l60-E 2008 Silverado Crew Cab, 4.8 4l60-E 1998 GMC Yukon 4x4 L-31 Vortec, 4l60-E 2017 GMC Serra 4x4 5.3 Vortec, 4l60-E Do It In A Chevrolet

08-09-2007, 01:24 PM	#9
jchav62 1962 C-10 Join Date: Apr 2005 Location: Las Vegas, New Mexico Posts: 4,978	Re: Rearend question??? That's probably the part number or something. The numbers you are looking for should be close to that. Right below if I remember correctly. It should be 4 digits (41 11). Those are the numbers and divide them to get your ratio... 41/11=3.73. __________________ Joseph Chavez "See the USA in a Chevrolet!!" ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/ 1962 C10 Shortbed Fleetside 327/th350 GV overdrive 1974 C10 Longbed Fleetside 350/th350 "The Trash Truck" 1999 Chevy 2500 OBS, Longbed 5.7/4L80E 4x4 2015 GMC Sierra SLE 1500 4x4

08-09-2007, 02:05 PM	#10
gulfcoast66 64-66 CHEVY JUNKIE Join Date: Apr 2007 Location: Cypress ,Texas Posts: 1,516	Re: Rearend question??? Thanks alot everyone,I found somemore #'s 3817778 1141 gm 972. So I divided 41 and 11 and 3.72, Im going with 3.73 gears. where can I find a better highway gear, 3.42, at a decent price? __________________ 1966 C-10 Fleetside LWB, 350 Lt1 4l60-E 2008 Silverado Crew Cab, 4.8 4l60-E 1998 GMC Yukon 4x4 L-31 Vortec, 4l60-E 2017 GMC Serra 4x4 5.3 Vortec, 4l60-E Do It In A Chevrolet

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