Ring Gear Size???

ironduke2.5 · 08-04-2008, 03:47 PM

Hey guys found some info about the axle i need but i need to figure out what ring gear size i have. I dont want to remove anything because i drive the truck everyday. I still have all the RPO Codes in the glove box can someone tell me what codes are what? I have the 3.73gears in the rear and its a 2wd. How do i find out what size ring gear i have without removing anything?
Thanks

Twin-10s · 08-04-2008, 03:58 PM

what year truck?

ironduke2.5 · 08-04-2008, 06:25 PM

Hey Twin-10s,
Thanks for the pics and my truck is a 1991 s10.
I think its the 7.5" or the 7.625" how can i tell which one it has?
I cant really open it up to take a look because i drive it everyday and i cant have any downtime with it.
Thanks

2002Chad · 08-05-2008, 12:48 PM

Quote: Originally Posted by ironduke2.5

Hey Twin-10s,
Thanks for the pics and my truck is a 1991 s10.
I think its the 7.5" or the 7.625" how can i tell which one it has?
I cant really open it up to take a look because i drive it everyday and i cant have any downtime with it.
Thanks

they are the same.

ironduke2.5 · 08-05-2008, 02:35 PM

hey 2002chad they are not the same because the 7.5" ring gear needs the 26spline axle shaft and the 7.625" ring gear needs the 28spline axle shaft. I wish they were both the same but just a small bit of difference can cause a big deal. Am i going to have to open up my rear end and measure my ring gear or does someone know how to tell the difference without opening up the diff?
Thanks

ka_jd7and1 · 08-05-2008, 03:04 PM

The ring gears are exactly the same.

The only difference in those would be number of axle splines, and those would only be different due to the year of the rearend.

:edit: I think you would have a 7.5", 26 spline rear. The easiest way to tell would be pull the cover, pull an axle, and check.

S15vortecpwr · 08-08-2008, 12:26 AM

the gear are the same as stated, it depends on what the carrier is that is your 26-28 spline gear have nothing to do with that

***orangesonoma*** · 08-08-2008, 10:22 PM

yeah spline counts have nothing to do with the ring size...

BlazingSaddle · 08-08-2008, 11:28 PM

Of course they are diffferent. one is an eigth of an inch bigger than the other. The 91 probably has the bigger one. Carrier is determined by axle ratio. yours is a 3.73 so you have the series 3 carrier. Yes the axles have different splines. They are not neccesarily related to the size of the gear. A 7.5 can be installed with 28 splined axles if the carrier or posi is right.

What you need to know most of all is wether or not your truck has EVER had anything done to the rear end. If you cannot be sure, start from scrtch by determining your gear ratio without looking at rpo codes. there are mothods turning the wheel while counting how many times the driveshaft turns is one way. One wheel blocked other off the ground. Please look for an accurate descrption on how to do this on the web elsewhere. It can be found and its not hard.

The gear ratio determines the carrier. The axle spline count, if NOT known for sure, is best found by pulling an axle. of course the axle is held in by clips inside the rear, so if pulling the cover anyway, its best to just count teeth on the gears while there to get the ratio.

The reason no-one can tell you for sure is simple. WE don't know your truck. The early models all had 7.5 and later they went to 7.625 the problem is that they also changed spline counts and while al the changing was going on not all trucks were built the same. there is also a number stamped on the rear. I believe its on the front of the drivers side. this code should tell you what was the ORIGINAL setup of the rear. Since many parts interchange, someone can fix a rear by installing parts from different vehicles inside the pumpkin.

No one knows where that pumpkin has been unless you do. If you find the number, which requires lots of looking and cleaning, and you know for sure it has never been out, you'll be sure of what it means. Otherwise, I am with everyone else and suggest pulling the cover, a clip and an axle.

Hey, if you drive it everyday, why not leave it alone?

S15vortecpwr · 08-09-2008, 10:03 PM

ok if a 7.5 and a 7.625 id diff than why does RICHMOND list both of them the same.

FYI i put 7.5 3.73 2-series gears in my 94 with a 2-series torsen carrier. My truck orig had 7.625 2-series 3.08 peg leg as listed by GM. The ring size is listed the same because they are the same. I have since put over 30k miles on this truck and have had no problems.

little more info:
http://richmondgear.com/07pdfs/RG9.pdf

removing an axle takes about 1 hr or less. no reason why you can't do this onnite and drive to work the next morning

08-04-2008, 03:47 PM	#1
ironduke2.5 Registered User Age: 20 Join Date: Nov 2007 Posts: 119 Location: Pensacola,fl User is: OffLine	Ring Gear Size??? Hey guys found some info about the axle i need but i need to figure out what ring gear size i have. I dont want to remove anything because i drive the truck everyday. I still have all the RPO Codes in the glove box can someone tell me what codes are what? I have the 3.73gears in the rear and its a 2wd. How do i find out what size ring gear i have without removing anything? Thanks
	[Reply w/Quote]

08-04-2008, 03:58 PM	#2
Twin-10s UNDER CONSTRUCTION Age: 40 Join Date: Dec 2001 Posts: 3,847 Location: San Jose,CA User is: OffLine	Re: Ring Gear Size??? what year truck?
	[Reply w/Quote]

08-04-2008, 06:25 PM	#3
ironduke2.5 Registered User Age: 20 Join Date: Nov 2007 Posts: 119 Location: Pensacola,fl User is: OffLine	Re: Ring Gear Size??? Hey Twin-10s, Thanks for the pics and my truck is a 1991 s10. I think its the 7.5" or the 7.625" how can i tell which one it has? I cant really open it up to take a look because i drive it everyday and i cant have any downtime with it. Thanks Last edited by ironduke2.5 : 08-04-2008 at 06:29 PM.
	[Reply w/Quote]

08-05-2008, 12:48 PM	#4
2002Chad Stock Age: 29 Join Date: Dec 2005 Posts: 694 Location: Dallas, Tx User is: OffLine	Re: Ring Gear Size??? Quote: Originally Posted by ironduke2.5 Hey Twin-10s, Thanks for the pics and my truck is a 1991 s10. I think its the 7.5" or the 7.625" how can i tell which one it has? I cant really open it up to take a look because i drive it everyday and i cant have any downtime with it. Thanks they are the same.
	[Reply w/Quote]

08-05-2008, 02:35 PM	#5
ironduke2.5 Registered User Age: 20 Join Date: Nov 2007 Posts: 119 Location: Pensacola,fl User is: OffLine	Re: Ring Gear Size??? hey 2002chad they are not the same because the 7.5" ring gear needs the 26spline axle shaft and the 7.625" ring gear needs the 28spline axle shaft. I wish they were both the same but just a small bit of difference can cause a big deal. Am i going to have to open up my rear end and measure my ring gear or does someone know how to tell the difference without opening up the diff? Thanks
	[Reply w/Quote]


S10Forum is the premier S-Series Site on the internet. Registered Users do not see the above ads. Please Register - It's Free!

08-05-2008, 03:04 PM	#6
ka_jd7and1 Registered User Age: 23 Join Date: Jun 2005 Posts: 2,184 Location: Bakersfield, CA User is: OffLine	Re: Ring Gear Size??? The ring gears are exactly the same. The only difference in those would be number of axle splines, and those would only be different due to the year of the rearend. :edit: I think you would have a 7.5", 26 spline rear. The easiest way to tell would be pull the cover, pull an axle, and check. Last edited by ka_jd7and1 : 08-05-2008 at 03:07 PM.
	[Reply w/Quote]

08-08-2008, 12:26 AM	#7
S15vortecpwr goin broke but n style Age: 28 Join Date: Jan 2007 Posts: 2,463 Location: Alabama User is: OffLine	Re: Ring Gear Size??? the gear are the same as stated, it depends on what the carrier is that is your 26-28 spline gear have nothing to do with that
	[Reply w/Quote]

08-08-2008, 10:22 PM	#8
*orangesonoma* registered s10 sex offender Age: 30 Join Date: Oct 2002 Posts: 37,742 Location: Indian Trail, NC User is: OffLine	Re: Ring Gear Size??? yeah spline counts have nothing to do with the ring size...
	[Reply w/Quote]

08-08-2008, 11:28 PM	#9
BlazingSaddle Registered User Join Date: Aug 2006 Posts: 69 Location: User is: OffLine	Re: Ring Gear Size??? Of course they are diffferent. one is an eigth of an inch bigger than the other. The 91 probably has the bigger one. Carrier is determined by axle ratio. yours is a 3.73 so you have the series 3 carrier. Yes the axles have different splines. They are not neccesarily related to the size of the gear. A 7.5 can be installed with 28 splined axles if the carrier or posi is right. What you need to know most of all is wether or not your truck has EVER had anything done to the rear end. If you cannot be sure, start from scrtch by determining your gear ratio without looking at rpo codes. there are mothods turning the wheel while counting how many times the driveshaft turns is one way. One wheel blocked other off the ground. Please look for an accurate descrption on how to do this on the web elsewhere. It can be found and its not hard. The gear ratio determines the carrier. The axle spline count, if NOT known for sure, is best found by pulling an axle. of course the axle is held in by clips inside the rear, so if pulling the cover anyway, its best to just count teeth on the gears while there to get the ratio. The reason no-one can tell you for sure is simple. WE don't know your truck. The early models all had 7.5 and later they went to 7.625 the problem is that they also changed spline counts and while al the changing was going on not all trucks were built the same. there is also a number stamped on the rear. I believe its on the front of the drivers side. this code should tell you what was the ORIGINAL setup of the rear. Since many parts interchange, someone can fix a rear by installing parts from different vehicles inside the pumpkin. No one knows where that pumpkin has been unless you do. If you find the number, which requires lots of looking and cleaning, and you know for sure it has never been out, you'll be sure of what it means. Otherwise, I am with everyone else and suggest pulling the cover, a clip and an axle. Hey, if you drive it everyday, why not leave it alone?
	[Reply w/Quote]

08-09-2008, 10:03 PM	#10
S15vortecpwr goin broke but n style Age: 28 Join Date: Jan 2007 Posts: 2,463 Location: Alabama User is: OffLine	Re: Ring Gear Size??? ok if a 7.5 and a 7.625 id diff than why does RICHMOND list both of them the same. FYI i put 7.5 3.73 2-series gears in my 94 with a 2-series torsen carrier. My truck orig had 7.625 2-series 3.08 peg leg as listed by GM. The ring size is listed the same because they are the same. I have since put over 30k miles on this truck and have had no problems. little more info: http://richmondgear.com/07pdfs/RG9.pdf removing an axle takes about 1 hr or less. no reason why you can't do this onnite and drive to work the next morning
	[Reply w/Quote]

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)