Differential clutch pack question
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Intermediate
Joined: Oct 2021
Posts: 26
Likes: 36
Differential clutch pack question
I am looking to rebuild my diff for my "71 in the next couple of weeks to continue my rear end refresh. I have no idea what state any of the internals are currently in and plan to put new bearings in as well as seals....etc.
I also plan to redo the LSD with new clutch pack too, but I have seen a number of different clutch pack options, either carbon fiber in the $200 range or steel in the $400 range. I have seen the comments that the carbon clutch packs are not good, but have never seen a reasoning? Why are they considered garbage? I have also read that the steel clutch packs wear out in 60k miles?!
Any insights would be appreciated.
I also plan to redo the LSD with new clutch pack too, but I have seen a number of different clutch pack options, either carbon fiber in the $200 range or steel in the $400 range. I have seen the comments that the carbon clutch packs are not good, but have never seen a reasoning? Why are they considered garbage? I have also read that the steel clutch packs wear out in 60k miles?!
Any insights would be appreciated.
Race Director
Joined: May 2006
Posts: 18,690
Likes: 2,572
I am looking to rebuild my diff for my "71 in the next couple of weeks to continue my rear end refresh. I have no idea what state any of the internals are currently in and plan to put new bearings in as well as seals....etc.
I also plan to redo the LSD with new clutch pack too, but I have seen a number of different clutch pack options, either carbon fiber in the $200 range or steel in the $400 range. I have seen the comments that the carbon clutch packs are not good, but have never seen a reasoning? Why are they considered garbage? I have also read that the steel clutch packs wear out in 60k miles?!
Any insights would be appreciated.
I also plan to redo the LSD with new clutch pack too, but I have seen a number of different clutch pack options, either carbon fiber in the $200 range or steel in the $400 range. I have seen the comments that the carbon clutch packs are not good, but have never seen a reasoning? Why are they considered garbage? I have also read that the steel clutch packs wear out in 60k miles?!
Any insights would be appreciated.
Tech Contributor
Joined: Aug 1999
Posts: 15,154
Likes: 3,959
From: Connecticut, USA
1971 Eaton Posi
You may have solid steel clutches or what I call snowflake clutches since they look like a paper snowflake from grade school days. Most 71's had solid steels. The 72-79 had the snowflake clutches and they were an attempt to resolve posi chatter, which was a problem with this posi setup since 1965. It didn't work and only made the clutches weaker, often with abuse they broke into pieces.
You need to first confirm the posi isn't cracked, if you find a crack, even a small one, the posi is junk and needs to be replaced. If the posi checks out you can use it as is, I never do and install new clutches.
New clutch choices today
Whoever said solid steel clutches only last 60k miles is clueless.
You may have solid steel clutches or what I call snowflake clutches since they look like a paper snowflake from grade school days. Most 71's had solid steels. The 72-79 had the snowflake clutches and they were an attempt to resolve posi chatter, which was a problem with this posi setup since 1965. It didn't work and only made the clutches weaker, often with abuse they broke into pieces.
You need to first confirm the posi isn't cracked, if you find a crack, even a small one, the posi is junk and needs to be replaced. If the posi checks out you can use it as is, I never do and install new clutches.
New clutch choices today
- Snowflakes- yes vendors are still selling them even though they are known to break
- Solid steels, I use these all the time. I tune posi's using these clutches.
- Fiber, I have plenty of these in stock at low prices, but I rarely use them. They resolved the issue of posi chatter because they smudge at every turn. Over time the fiber ends up in the oil, the clutches have play and they start to chatter again. They cannot be tuned, only used with the heavy springs they come with. At that point the answer is to buy another clutch kit and install it. Not what I would recommend but some like them. Most don't know anything about them.
Whoever said solid steel clutches only last 60k miles is clueless.
Melting Slicks
Joined: Nov 2006
Posts: 3,393
Likes: 1,806
From: Apple Valley, MN
The carbon plates typically will wear out at twice the rate of steel. When cold, they will slip as they need to be at operating temperature to function as designed.
Measure your steel plates. They may be good for reuse.
Measure your steel plates. They may be good for reuse.
Pro
Joined: Jun 2023
Posts: 506
Likes: 300
From: Western N.C.
