Posi Rebuild Questions - 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 07-30-2013, 02:58 PM
Registered User
 
Last photo:
Join Date: Mar 2009
Location: Burton, MI
Posts: 817
Wiki Edits: 0

Thanks: 39
Thanked 18 Times in 17 Posts
Posi Rebuild Questions

background: one of my rear drum brakes was holding when it shouldn't have been.. I did a peg-leg burnout and absolutely WASTED my posi clutches. I'm tried of driving around on one-tire-fire :>

I was going to farm the job out.. but after seeing the rebuild on PowerBlock, I'm reasonably confident I can do the job myself...

my question is.. I've finally located the parts I need.. (It's not easy finding GM 8.2" 10-bolt posi parts)

anyhow.. there are several packages listed, they are 14 plate carbon clutches and
18, and 22 plate steel clutches
and 14 plate DuraGrip clutches

Is this a option that is up to me on how 'tight' the clutch pack is? or is this somthing I'm going to have to tear my existing pack apart first, and count the plates and match it kind of thing?

I street drive this car a LOT.. and it sees some time on the track with slicks.. I know slicks and posi aren't the best combo, but i'm not willing to switch to a locker at this time. What would be the best clutch material to go with?

(ideally, I want that Eaton electric locker / posi combo, but I don't think they make it for the 8.2" 10-bolt)

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-30-2013, 03:03 PM
Registered User
 
Last photo:
Join Date: Mar 2009
Location: Burton, MI
Posts: 817
Wiki Edits: 0

Thanks: 39
Thanked 18 Times in 17 Posts
ah, found a tech article on Randy's Ring and pinion that more or less answered my question
Quote:
There are currently four different clutch plate designs available, three of which are worth considering. We will begin with GM's service pack which uses 18 all-steel clutches with cut-outs for oil. These clutches tend to chatter, and the cut-outs that are supposed to decrease chatter make the plates weak and prone to breakage. The new 14-plate carbon fiber clutches from Eaton are my favorite. This design hooks up very well off-road and does not chatter when used with the 400 lb. springs. There is also an 18-plate, all steel design that does not use cut-outs. This design hooks up very well for off-road use and does not break. However, it does tend to chatter when used with 400 lb. or 800 lb. springs. Use these clutches for drag racing or an extreme off-road application where long life is important and chatter will not bother the driver. The most aggressive design from Eaton uses 22 plates, and chatters with any spring combination. These were designed for GM racing applications and work well until the thin tabs that engage with the case start to wear out. Use this package when extreme traction is needed and the clutches can be serviced often.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-31-2013, 06:19 AM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,090
Wiki Edits: 0

Thanks: 12
Thanked 446 Times in 379 Posts
Your OEM Eaton Posi will have the 18 disc solid steel clutches. This is the set that I recommend. The carbon fiber plates can glaze over if you slip them, and there is ponly 14 disc, which is a large reduction in surface area when compared to the 18 disc set. You can also upgrade to the 400 pound springs if you want. I've installed several sets of the 400 pound springs with the 18 disc clutch and had no problems with it. Just be sure to use the GM oil additive and not some other brand. Watch the youtube videos by Tom's Differentials as to how to set up the clutches. Most of the time the guys on Power Block just screw up stuff, so I usually don't recommend using their methods.
Reply With Quote Quick reply to this message
The Following User Says Thank You to big gear head For This Useful Post:
Crosley (08-01-2013)
  #4 (permalink)  
Old 08-01-2013, 09:52 AM
Registered User
 
Last photo:
Join Date: Mar 2009
Location: Burton, MI
Posts: 817
Wiki Edits: 0

Thanks: 39
Thanked 18 Times in 17 Posts
Thanks for the info. This axle has been rebuilt before. I have no idea by who. I bought it from a friend, who got it with a car he bought. so I'm not exactly sure if it's all GM or not inside.

one of these days I'd love to upgrade to a dana 60 axle so I could have that eaton posi with electric locker :>
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-01-2013, 03:10 PM
Registered User
 
Last photo:
Join Date: Nov 2006
Location: Woodstock
Posts: 932
Wiki Edits: 0

Thanks: 2
Thanked 79 Times in 72 Posts
The carbon fiber clutches are supposed to stand up to thermal loads better than the old standard clutches if you happen to slip them.

You cant use the carbon fiber clutches with the 800 lb preload springs.
I always thought the stock Eaton LSD units camne with the 400 lb springs and carbon fiber clutches??

peace
Hog
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-01-2013, 04:41 PM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,090
Wiki Edits: 0

Thanks: 12
Thanked 446 Times in 379 Posts
Carbon fiber clutches will not handle heat from slipping. I've got some on my bench to prove it.

The old original Eaton Posi had the 18 disc steel clutches and 200 pound springs. The new Eaton Posi that you can buy today has the carbon fiber clutches and 400 pound springs. The old Eaton had 18 tooth axle gears, except for the special units built for the COPO cars, which has special forged heat treated 17 tooth axle gears. The new Eaton has powdered metal 17 tooth axle gears.
Reply With Quote Quick reply to this message
The Following User Says Thank You to big gear head For This Useful Post:
Crosley (08-04-2013)
  #7 (permalink)  
Old 08-01-2013, 05:08 PM
Registered User
 
Last photo:
Join Date: Nov 2006
Location: Woodstock
Posts: 932
Wiki Edits: 0

Thanks: 2
Thanked 79 Times in 72 Posts
Quote:
Originally Posted by big gear head View Post
Carbon fiber clutches will not handle heat from slipping. I've got some on my bench to prove it.

The old original Eaton Posi had the 18 disc steel clutches and 200 pound springs. The new Eaton Posi that you can buy today has the carbon fiber clutches and 400 pound springs. The old Eaton had 18 tooth axle gears, except for the special units built for the COPO cars, which has special forged heat treated 17 tooth axle gears. The new Eaton has powdered metal 17 tooth axle gears.
OK that makes sense, I was referring to Eaton products that you can currently purchase.

I dont doubt that you do have some fried clutches. You can fry any clutch, no matter the material. Is this a customer unit or personal?

What does the older stuff look like, with similar use/abuse?

Eaton is advertising their carbon clutches to be better at handling thermal stresses.

OP:
Here is the complete Eaton, as of Jan 2013. No elocker for your type of 8.2 with 28 spline, or my drop out 8.2 with 17 splines axles. http://www.eaton.com/ecm/groups/publ.../ct_128302.pdf


peace
Hog
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-01-2013, 06:09 PM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,090
Wiki Edits: 0

Thanks: 12
Thanked 446 Times in 379 Posts
The burnt clutches that I have are from a customer's Chevelle that was drag raced. Water burnouts are very hard on clutch type differentials. I installed a set of the 18 disc clutches and shimmed them tight and I havn't heard from him agian. This was a few years ago.

The old steel clutches usually don't get damaged from the heat. I have seen one or two sets that were blue, but I've changed a hundred or more and most of them are just gray and silver. I think Tom also uses the 18 disc steel set, and all of the 33 spline units that I have installed had the steel clutches in them.
Reply With Quote Quick reply to this message
The Following User Says Thank You to big gear head For This Useful Post:
Crosley (08-01-2013)
  #9 (permalink)  
Old 08-01-2013, 06:09 PM
Registered User
 
Last photo:
Join Date: Jul 2004
Location: At Speed
Age: 51
Posts: 1,374
Wiki Edits: 0

Thanks: 2
Thanked 36 Times in 34 Posts
No clutch posi will tolerate for very long having one tire going 100 mph and the other tire standing still, mainly cause all the oil is slung out of the clutch pack.

A Detroit locker bangs and clunks and pops but you probably cant break or wear it out even in a circle track car. Even when traveling at a steady cruise with a light load, the backlash in the locker can be noticed in a smooth riding car on the interstate. I have put a few Detroit lockers in and took them right back out when people just couldnt stand the oscillating.
Reply With Quote Quick reply to this message
The Following User Says Thank You to lmsport For This Useful Post:
Crosley (08-04-2013)
  #10 (permalink)  
Old 08-01-2013, 06:16 PM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,090
Wiki Edits: 0

Thanks: 12
Thanked 446 Times in 379 Posts
Yea, you have to be willing to put up with the noise and the jerking. It doesn't bother me, but many people just can't stand it.
Reply With Quote Quick reply to this message
The Following User Says Thank You to big gear head For This Useful Post:
Crosley (08-01-2013)
  #11 (permalink)  
Old 08-04-2013, 08:27 AM
Registered User
 
Last photo:
Join Date: Nov 2006
Location: Woodstock
Posts: 932
Wiki Edits: 0

Thanks: 2
Thanked 79 Times in 72 Posts
I have a reg cab shortbox 2wd truck (1997) I had a Lockrite in it, when travelling down the freeway at about 70mph with 325/50-15 drag radials on teh back. IWhen entering a gentle curve I could feel the truck wanting to drive straight and was fighting my steering inputs.

I also remember wetting slicks in the waterbox, then pulling forward and starting my burnout. The 1 side burned out and smoked niclely, the other side didnt spin at all. ANd thatw as with the locker. It was toast. On teh way home, power was only getting to to one tire and it would push forward and to the side at the same time, literally rocking my truck as I drove down the road.

peace
Hog
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:
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
Eaton Posi rebuild big gear head Transmission - Rearend 0 09-02-2012 07:51 AM
Eaton posi questions... ap72 Transmission - Rearend 7 06-23-2008 06:35 PM
GM 10-bolt 7.5 posi questions... 67cuda Transmission - Rearend 2 03-20-2006 07:41 PM
some questions about posi's Dreadlord Transmission - Rearend 4 02-02-2004 11:31 PM
ford 9" traction lock posi rebuild 406 ss monte Transmission - Rearend 1 01-16-2004 07:59 PM


All times are GMT -6. The time now is 07:00 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.