Jump to content



Photo
- - - - -

What Size Is My Ring Gear?!


  • Please log in to reply
6 replies to this topic

#1 Korbin502

Korbin502

    Enthusiast

  • Member
  • 56 posts
  • Location:California
  • Gender:Male

Posted 17 January 2010 - 03:36 PM

I have read many of the older posts and half of the responses are 10.5 and the other half is 11.5. I am ready to pull everything apart I just need to know which parts I need to get. I have a 2001 GMC Sierra 2500HD with an Allison Trans. Is there a tag I can look at somewhere? I know I have 4:10 gears. That is as far as my knowledge goes.

Posted Image

Posted Image

01 GMC SIERRA 2500HD SLT 4X4 8.1 ALLISON 174,000 MILES
1996 Chevy LT3500 Dually Vortec 454


#2 jrod332

jrod332

    Enthusiast

  • Member
  • 438 posts
  • Location:Amherst NH
  • Gender:Male

Posted 17 January 2010 - 04:24 PM

There should be an RPO code sticker in your glove box thats full of codes. I believe the code should start with a G. use this link here to type in codes.

http://www.gm-trucks...ookup/?find=zjp

#3 ybsane

ybsane

    Enthusiast

  • Member
  • 154 posts
  • Location:Charlotte,NC

Posted 17 January 2010 - 06:03 PM

I have read many of the older posts and half of the responses are 10.5 and the other half is 11.5. I am ready to pull everything apart I just need to know which parts I need to get. I have a 2001 GMC Sierra 2500HD with an Allison Trans. Is there a tag I can look at somewhere? I know I have 4:10 gears. That is as far as my knowledge goes.


In the all the vendor books I have, the 02 to present has the 11.5" gear assembly. There are 31 pinion splines on the 11.5" and 30 pinion splines on the 10.5" if you want to check that way.

I am 99.9% sure that you have the older 10.5" assembly,in your 01 truck.

Don't forget that if you remove the whole assembly out and just get the new bearings pressed in, you don't have to mess with the ring and pinion shims. This way your patterns will remain correct prior to removal.
It's not the truck.! But the arm hanging out the window that counts.
2007 Suburban,5.3 3.73 Gears,Auburn Posi,Brother Bill's axels.
K&N drop in, Magnaflow exhaust. PCMforless tune-by Alvin...
Performabuilt Transmission.

#4 Korbin502

Korbin502

    Enthusiast

  • Member
  • 56 posts
  • Location:California
  • Gender:Male

Posted 18 January 2010 - 09:04 AM

I have read many of the older posts and half of the responses are 10.5 and the other half is 11.5. I am ready to pull everything apart I just need to know which parts I need to get. I have a 2001 GMC Sierra 2500HD with an Allison Trans. Is there a tag I can look at somewhere? I know I have 4:10 gears. That is as far as my knowledge goes.


In the all the vendor books I have, the 02 to present has the 11.5" gear assembly. There are 31 pinion splines on the 11.5" and 30 pinion splines on the 10.5" if you want to check that way.

I am 99.9% sure that you have the older 10.5" assembly,in your 01 truck.

Don't forget that if you remove the whole assembly out and just get the new bearings pressed in, you don't have to mess with the ring and pinion shims. This way your patterns will remain correct prior to removal.



Got everything pulled apart last night. I have the 10.5 Ring Gear. So, I guess the rule about all 8.1's having an 11.5 rear end are wrong. Also noticed the rear end can be adjusted from side to side with the help of some sort of threaded cups on either side of the diff. I need to get a certain tool to be able to adjust them. Had a problem getting the yoke balancer off of the Pinion.The balancer kept trying to slide off of the yoke! I am sure this will throw it off balance. I need to find out if I can take this to a driveline shop and have it fixed or if will I need a new one. I am hoping to have it all done today. I will be back with an update this evening.

Posted Image

Posted Image

01 GMC SIERRA 2500HD SLT 4X4 8.1 ALLISON 174,000 MILES
1996 Chevy LT3500 Dually Vortec 454


#5 Larry

Larry

    Member Since 1997

  • Member
  • 538 posts
  • Location:Southern Colorado
  • Gender:Male

Posted 22 January 2010 - 06:18 PM

I have read many of the older posts and half of the responses are 10.5 and the other half is 11.5. I am ready to pull everything apart I just need to know which parts I need to get. I have a 2001 GMC Sierra 2500HD with an Allison Trans. Is there a tag I can look at somewhere? I know I have 4:10 gears. That is as far as my knowledge goes.


In the all the vendor books I have, the 02 to present has the 11.5" gear assembly. There are 31 pinion splines on the 11.5" and 30 pinion splines on the 10.5" if you want to check that way.

I am 99.9% sure that you have the older 10.5" assembly,in your 01 truck.

Don't forget that if you remove the whole assembly out and just get the new bearings pressed in, you don't have to mess with the ring and pinion shims. This way your patterns will remain correct prior to removal.



Got everything pulled apart last night. I have the 10.5 Ring Gear. So, I guess the rule about all 8.1's having an 11.5 rear end are wrong. Also noticed the rear end can be adjusted from side to side with the help of some sort of threaded cups on either side of the diff. I need to get a certain tool to be able to adjust them. Had a problem getting the yoke balancer off of the Pinion.The balancer kept trying to slide off of the yoke! I am sure this will throw it off balance. I need to find out if I can take this to a driveline shop and have it fixed or if will I need a new one. I am hoping to have it all done today. I will be back with an update this evening.


That is interesting. I have yet to see a Duramax or 8.1L in a GMT800 not have an 11.5” ring gear. The 10.5” isn’t rated for the 8.1L (or Duramax) behind an Allison in an HD truck. Suburban or G-van with an 8.1L and 4L80E, yes….HD truck no. I would love to see a picture of your rear axle with the cover on it. Are you the original owner? If your 8.1L trucks indeed has a 10.5” I very seriously doubt it is original.

Posted Image

GM quit building great trucks in 1972
GM quit building good trucks in 1987
GM quit building decent trucks in 2006
GM quit building trucks in 2007. What a pity to have such a great powertrain in such an ill conceived package.  GMT900's are ugly with the body assembly quality of a complete truck built entirely of ill-fitting counterfeit Taiwanese body panels

2014 looks promising though!  GM's back in business!

9795938793_b6567488f2_z.jpg


#6 Korbin502

Korbin502

    Enthusiast

  • Member
  • 56 posts
  • Location:California
  • Gender:Male

Posted 05 February 2010 - 12:03 AM

I have read many of the older posts and half of the responses are 10.5 and the other half is 11.5. I am ready to pull everything apart I just need to know which parts I need to get. I have a 2001 GMC Sierra 2500HD with an Allison Trans. Is there a tag I can look at somewhere? I know I have 4:10 gears. That is as far as my knowledge goes.


In the all the vendor books I have, the 02 to present has the 11.5" gear assembly. There are 31 pinion splines on the 11.5" and 30 pinion splines on the 10.5" if you want to check that way.

I am 99.9% sure that you have the older 10.5" assembly,in your 01 truck.

Don't forget that if you remove the whole assembly out and just get the new bearings pressed in, you don't have to mess with the ring and pinion shims. This way your patterns will remain correct prior to removal.



Got everything pulled apart last night. I have the 10.5 Ring Gear. So, I guess the rule about all 8.1's having an 11.5 rear end are wrong. Also noticed the rear end can be adjusted from side to side with the help of some sort of threaded cups on either side of the diff. I need to get a certain tool to be able to adjust them. Had a problem getting the yoke balancer off of the Pinion.The balancer kept trying to slide off of the yoke! I am sure this will throw it off balance. I need to find out if I can take this to a driveline shop and have it fixed or if will I need a new one. I am hoping to have it all done today. I will be back with an update this evening.


That is interesting. I have yet to see a Duramax or 8.1L in a GMT800 not have an 11.5" ring gear. The 10.5" isn't rated for the 8.1L (or Duramax) behind an Allison in an HD truck. Suburban or G-van with an 8.1L and 4L80E, yes….HD truck no. I would love to see a picture of your rear axle with the cover on it. Are you the original owner? If your 8.1L trucks indeed has a 10.5" I very seriously doubt it is original.

Posted Image


Sorry for the delay. My truck DOES have an 11.5" Ring Gear. No doubt about it. After pulling everything apart, I measured and counted splines. I will say this, it is not a do it yourself job. You need someone with the knowledge of adjusting everything to fit just right. Thanks to all for the help!

Posted Image

Posted Image

01 GMC SIERRA 2500HD SLT 4X4 8.1 ALLISON 174,000 MILES
1996 Chevy LT3500 Dually Vortec 454


#7 doug_scott

doug_scott

    Senior Enthusiast

  • Member
  • 2,378 posts
  • Name:Doug Scott
  • Location:Ajax, ON
  • Gender:Male
  • Drives:2010 GMC SL Ext Cab 4.8

Posted 18 January 2011 - 08:34 AM

Posted Image



The pics above seem odd to me. Why is the ring gear on the right side of the pinion gear on the 10.5"? Every vehicle I have seen has the ring gear on the left side of the pinion gear. Having it on the right side means the pinion is turning in the opposite direction to go foward.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users