Question about loose axle in Chevy 12 bolt rear end - 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 07-08-2010, 05:17 PM
Registered User
 

Last journal entry: Bringing home the 401 Nailhead
Last photo:
Join Date: Jul 2006
Location: NE Ohio
Posts: 381
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Question about loose axle in Chevy 12 bolt rear end

Wife has a Chevy 12 bolt rear end in her 39 Willys. It has been street driven with no problems for 2 years. She made two 1/4 passes on the street tires. We put on a set of slicks to help with launch but never made back to the track. I put the street tires back on and noticed a vibration at about 45 mph. I thought I must have left one or more lug nuts loose. I jacked it up and checked. Both sides were tight but did notice that if I grab the passenger tire and pull straight out it will move (less than a 1/4"). Drivers side is tight.

A local racer that has always been reliable said this is normal and to look else where for the vibration. Still doesn't seem right to me. Should there be any in and out motion of the axle?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-08-2010, 05:25 PM
adantessr's Avatar
'23 T-Bucket Pickup
 
Last wiki edit: Troubleshooting ignition Last photo:
Join Date: Jun 2010
Location: South Charleston , WV
Age: 62
Posts: 1,549
Wiki Edits: 3

Thanks: 43
Thanked 17 Times in 15 Posts
Loose axle

Yes the movement is normal on the axle . Uses a c-clip on the side gear in the differential to retain the axle . Look elsewhere for the vibration . Did you put the tires on the same side they came off of . Oftentimes reversing the direction of rotation on a radial tire will cause the belts to seperate and cause vibrations. If that is the case the tires will need to be replaced .
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-08-2010, 06:31 PM
Registered User
 
Last photo:
Join Date: Apr 2010
Location: Hawaii
Posts: 373
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What kind of wheels do you have? Sometimes uni-lug wheels (if that's what you have) don't center-up well without hub-centric rings.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-09-2010, 06:01 AM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,030
Wiki Edits: 0

Thanks: 10
Thanked 400 Times in 343 Posts
If this rear end has a limited slip differential (posi) then the axle end play can be reduced by replacing the clutches or shimming the clutches for the correct preload. If this is an Eaton Posi then this isn't a big deal. If it has a Auburn then you have to replace the whole differential because they can not be repaired. If you have a standard differential then the rear end might have been subjected to a lot of one wheel burnouts and the thrust washers behind the axle gears might be worn, which would cause the excess axle end play. If the rear end is set up right then the axle end play should be around .005 inch to slightly more. I agree that this will not cause the vibration.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-09-2010, 08:48 AM
Registered User
 

Last journal entry: Some More Roll Cage Fabrication
Last photo:
Join Date: Apr 2010
Location: Ohio
Age: 31
Posts: 233
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 3 Posts
I agree the axle moving in and out is most likely not the source of your vibration. Just speculating maybe the weights could have fallen off during the 1/4 mile passes on street tires. I would balance the tires. A general rule of thumb is if you feel it in the seat it is the rear. If you feel it in your feet/floorboards near pedals or steering wheel but not seat it is the fronts. But would it hurt to balance them all? Try to find a place that can road force balance them(it is the best).

Big Gear Head most likely worn differential gears or thrust washers would not cause an axle to move in and out that far. A worn cross shaft pin, end of axle worn, or wrong c-clip thickness, or least likely a fabbed axle that is slightly off in length at the end(ie worn end) would allow that much play. You are correct worn gears or shims would increase amount of play slightly. Also, an incorrecly setup center section could could be the cause of that(ie too much slop in diff gears and floaters). But one would think that play would have been noticed before. Hard to say.

However, I would be concerned that the axle is moving that much. I would worry about the brakes. If it is drums the shoes and backing plate could get damaged. If it is discs the rotor could spread the pads apart during cornering and this could affect brake balance and life. I wouldn't say it is a huge deal but you might want to add it to the list of stuff to get done.

Good luck.

Last edited by ethn_bert; 07-09-2010 at 09:13 AM.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-09-2010, 10:05 PM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,030
Wiki Edits: 0

Thanks: 10
Thanked 400 Times in 343 Posts

You can't see it very well in this picture, but wear in this area of the differential is caused by doing one wheel burnouts. This will wear the case, thrust washer and the back side of the axle gear. This will cause excessive axle end play in a standard differential. Most of the time and axle that has excessive end play will be in a limited slip differential with worn clutches or worn cones, which can be fixed by replacing the clutches or the differential.
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
4x4 12 bolt rear end same as 2wd rear end??? Ed ke6bnl Transmission - Rearend 2 05-24-2008 02:25 PM
12 bolt posi rear end fluid 1972bigblockchev Transmission - Rearend 3 06-19-2007 09:46 AM
Transfer case - NP 203 - 205 jrm123180 Transmission - Rearend 2 03-24-2006 07:36 AM
How to identify the year of a Chevy 10 bolt rear End? frankenvette Transmission - Rearend 2 04-07-2005 10:14 PM
Rear End Axle Code for the Chevy S -10's Traps Restoration Transmission - Rearend 1 02-27-2005 10:05 PM


All times are GMT -6. The time now is 10:59 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.