GM 12 bolt Pinion Depth - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 04-27-2009, 01:01 PM
Registered User
 
Join Date: Apr 2009
Location: Orlando Florida
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
GM 12 bolt Pinion Depth

My 69 camaro has 12 bolt 4:56 rear end. One teeth was broken off the ring gear. I am presently replacing with Richmond gears 3:73. I took everthing apart and cleaned it, press in new bearing on the carrier and racers on the axle housing. I installed the bearing on the pinion and it's temporary in the housing without the crush coller. My choice of depth tool is 81655 - JEGS Ring & Pinion Set Up Tool Kit . The instruction are hard to understand, but got good idea from this guy at http://www.angelfire.com/theforce/5o...a5ohtech024.ht
My two questions are:
1- if you look at the head of the pinion as a clock and take measurements with the dial indicator placing the extension tip on end position 9 o'clock and then position 3 0'clock the reading are equal, but when placing in the 12 o'clock and 6 o'clock position the 6 0'clock readings are higher then 12.
The pinion rotation is fine. Pinion bearing, Pinion bore racers are all sitting flush.
2-Is the housing pinion bore setup in an angle?
.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-27-2009, 01:19 PM
prostreet6t9's Avatar
Differential/Driveline
 
Last photo:
Join Date: Sep 2008
Location: oregon
Age: 51
Posts: 1,724
Wiki Edits: 0

Thanks: 8
Thanked 40 Times in 37 Posts
Do you Know what series carrier you have?
Did you reuse the original pinion shim?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-27-2009, 03:12 PM
cranky1's Avatar
Just stuck
 
Last photo:
Join Date: Apr 2008
Location: Pasagetdowndena, TX
Age: 63
Posts: 434
Wiki Edits: 0

Thanks: 14
Thanked 0 Times in 0 Posts
I have an old Pro Parts setup tool and it doesn't look anything like that one but the last one I setup, I just used my depth mic to do it after I confirmed the bearing cap and fit was actually on the centerline. Anyways, my setup tool uses a magnetic target plate that just sticks to the pinion head and the indicator measures to it from centerline....and I use 'dummy' bearings to set the pinion and once that's done, then the permanent bearings go on. If you install the new bearing and have to make an adjustment, you may mess it up pressing it back off.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-27-2009, 04:26 PM
Registered User
 
Join Date: Apr 2009
Location: Orlando Florida
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I wish I would had thought about that. I already press on the new bearing with the orginal shim. But what I am trying to find out, if it is normal to have these measurement. Top edge of pinion head .506, bottom is .513 the left side is .511 and the right side edge is .510. I didn't do the subtraction or addition yet to get the proper shim.
I am confuse, how could you have a pinion flat in its bore not measuring the same or at least close as the right and left measurements.
I have a carrier series 4
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-27-2009, 04:45 PM
cranky1's Avatar
Just stuck
 
Last photo:
Join Date: Apr 2008
Location: Pasagetdowndena, TX
Age: 63
Posts: 434
Wiki Edits: 0

Thanks: 14
Thanked 0 Times in 0 Posts
Does the middle of the pinion head have a raised face? Are you getting those numbers from the machined face where the teeth end? I use the middle of the gear head for my measurements. Sometimes they are machined smooth and sometimes they are not. I'll use my magnetic target plate if they are rough machined and subtract the thickness of it. Do you have the front installed and snug?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-27-2009, 04:56 PM
Registered User
 
Join Date: Apr 2009
Location: Orlando Florida
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks Cranky1 First problem is solved, I didn't have my tool bar mounted correctly as in the picture in the instruction and when said, you measure from centerline of pinion with your tool. I measure as close to the center of the pinion head and the numbers came out equal on all four corners. Now to the next step.
Thank you
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-27-2009, 06:35 PM
cranky1's Avatar
Just stuck
 
Last photo:
Join Date: Apr 2008
Location: Pasagetdowndena, TX
Age: 63
Posts: 434
Wiki Edits: 0

Thanks: 14
Thanked 0 Times in 0 Posts
Good deal. Meant to say front bearing installed. A buddy used to just try and do that without it and never got good numbers lol
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 04-29-2009, 09:13 AM
Registered User
 
Join Date: Apr 2009
Location: Orlando Florida
Posts: 7
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
From bearing is installed without the crush coller.
Now I having problems understanding instruction using my toolhttp://www.jegs.com/InstallationInstructions/500/555/555-81655.pdf
On step 4 it tells you to measure the carrier bore. I used the 2.3 extension and got 0.814 and I assume you subtract 2.3 from that number and get 1.486.

Step 5 measure the pinion head which is 0.504 and I subtraction the 3.3 extension and got 2.796. The Pinion is etched from Richmond gear for 2.830. And this is where I got confuse, the last sentence in step 5 said, record the measurements and add or subtract the offset?

My question is when do I subtract or add and to what number?
Do they mean add carrier bore to pinion distance 1.486 + 2.796 = 4.282
or subtract 1.486-2.796= 1.31
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 04-29-2009, 07:11 PM
cranky1's Avatar
Just stuck
 
Last photo:
Join Date: Apr 2008
Location: Pasagetdowndena, TX
Age: 63
Posts: 434
Wiki Edits: 0

Thanks: 14
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by mycars51
From bearing is installed without the crush coller.
Now I having problems understanding instruction using my toolhttp://www.jegs.com/InstallationInstructions/500/555/555-81655.pdf
On step 4 it tells you to measure the carrier bore. I used the 2.3 extension and got 0.814 and I assume you subtract 2.3 from that number and get 1.486.

Step 5 measure the pinion head which is 0.504 and I subtraction the 3.3 extension and got 2.796. The Pinion is etched from Richmond gear for 2.830. And this is where I got confuse, the last sentence in step 5 said, record the measurements and add or subtract the offset?

My question is when do I subtract or add and to what number?
Do they mean add carrier bore to pinion distance 1.486 + 2.796 = 4.282
or subtract 1.486-2.796= 1.31
If the pinion is etched with a depth measurement, don't worry about the thickness of the gear head. Mounting distance and pinion depth are two different ways to set the pinion. If the gear wasn't marked, you would have to use the mounting distance method but since the pinion is marked, you will use the pinion depth method which is the distance from the ring gear center line (or center of the carrier bearing bore) to the 'back' face of the pinion...the face that you are looking at from the back of the rear. 2.380 is what you need from that face to the center line of the bores. Hopefully, the bore center line was machined on center. They are usually very close but never perfect. That tool looks a bit odd to me. Mine sets up with the bearing caps and dummy blanks holds a round rod that the indicator mounts into. And I never saw a set of aftermarket gears that were etched using the mounting distance dimension. They have always use pinion depth. I also don't think you measured your carrier bore right because your bearings should be much bigger than 1.628 in diameter (1/2 of 1.628 is .814). That's pretty small bearing for a carrier.....

Last edited by cranky1; 04-29-2009 at 07:29 PM.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 05-01-2009, 08:01 AM
cranky1's Avatar
Just stuck
 
Last photo:
Join Date: Apr 2008
Location: Pasagetdowndena, TX
Age: 63
Posts: 434
Wiki Edits: 0

Thanks: 14
Thanked 0 Times in 0 Posts
Did you get this together?
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




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

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
questions about swapping R/E gears from a 12 bolt Gm into a Pontiac 10 bolt housing l Bad Rat Transmission - Rearend 6 06-11-2007 10:50 AM
Where to Find a GM 12 Bolt Rear Axle reddogracing Transmission - Rearend 4 09-09-2006 04:48 PM
Need help with 12 bolt rear end pinion seal. cujoe822 Transmission - Rearend 10 09-07-2006 10:47 AM
F-body differentials, 9 bolt Borg Warner vs. GM 10 bolt Mad Maggot Transmission - Rearend 8 02-17-2005 08:02 PM
GM 12 Bolt Housing Codes jbspringer Transmission - Rearend 0 10-03-2002 03:43 PM


All times are GMT -6. The time now is 02:33 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.