Limeted slip Diff question
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From: Albuquerque
Limeted slip Diff question
A couple months ago I changed the rear diff oil and added 4 oz of friction modifier. The syn, fluid I put in didn't have any in it. I didn't get a good seal and had to drain and reseal the cover after about 1 month of driving. I recovered most of the fluid and after straining it through cheese cloth, had to add about half a quart more of oil. I'm only able to get the right rear tire to spin in the dirt! I guess I don't understand what the modifier does. Do I need to add more or is there too much in and isn't allowing both axels to drive. I did a search and couldn't really get a good answer. Thanks.
Hotshot
Joined: Feb 2007
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From: Sterling Heights,Mi
Please excuess the question, If I stand on my truck, only one wheel spins for about 20 feet before the second one kicks in on cement, dirt, its about a couple of feet.. How long were you on it?
And I dont think adding any more modifier will hurt anything.
And I dont think adding any more modifier will hurt anything.
Duct Tape Tech.
Joined: Jul 2009
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From: San Antonio Tx.
The friction moifier only allowes the clutches to slip without making noise.( It stops the popping noise when you turn ) It will not make the clutches slip or keep them from slipping. That is all, the clutch disc may be getting thin or the springs may be weak. IMHO.
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From: Milroy, PA
The factory limited slip is well worn out at 100k. Some people have claimed early as 50k. I remember seeing at one time, someone made a replacement clutch pack, that was higher in clutches (tighter) but cannot remember were. Only real solution to traction issues is to put a new carrier in your rear axle. I love my detroit, but a true trac is a quiet limited slip.
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Duct Tape Tech.
Joined: Jul 2009
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From: San Antonio Tx.
I don't if it will work for all rear ends, but we use to install an extra lined clutch and an extra flat disc in 9" ford rear ends when we were drag racing, They would hold better. But that was a while ago LOL
Last edited by Bob Taulbee; Sep 16, 2009 at 07:27 PM. Reason: wording error
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From: Dallas-Ft. Worth
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From: Haysville Ks.
When I goto the track I have to do a burn out and the right side will spin. Then I do it
again and the left will kick in. Then do it again and they both kick in. Thats on
pavement. In the dirt they both kick in right from the start. Like Ron I just changed the
fluid 2 months ago. I had the same problem with 1 wheel spinin.
again and the left will kick in. Then do it again and they both kick in. Thats on
pavement. In the dirt they both kick in right from the start. Like Ron I just changed the
fluid 2 months ago. I had the same problem with 1 wheel spinin.
Post Fiend
Joined: Feb 2008
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From: Lancaster, Pa.
Its funny because I was questioning this too not to long ago, changed my rear fluid out a while back at 100,000 with RP and had to add just half of a bottle of the friction modifier because of the scuffing issues around corners. I asked Huck at RRE if mine spun both tires on the track and he said it kicked in so my limited slip is apperantly working.
Logistics Pro
Joined: Nov 2006
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From: Fallon,NV & Bainbridge OH
I agree with Joe, to much modifier and you only make things worse. If it don't chatter now don't add more. You could either have to much (fluid may have had it in already) or you could have bad clutches or springs in the diff.
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From: Albuquerque
I might remover half quart of fluid, add some new ad see what happens. Like Dave said, my clutches might be warn. I just rolled 100k and the PO of the truck seemed to have used it as a grogery getter, so I'm supprised the clutches are warn, but.....
Hotshot
Joined: Feb 2007
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From: Sterling Heights,Mi
It's the opposite, Pat! Friction modifier ALLOWS the clutches to slip more reducing chatter. If you add too much, you'll have too much slipping. You want to add just enough to keep the clutches from chattering. I put in Royal Purple with it already in, and haven't tested it out yet. My tires aren't even a year old yet, so I'm a bit reluctant to do a burn out to see what happens.
so much to learn so much to learn so much to learn so much to learnThank you for that.. time to do the rear end "DOPE" change.. and while I am at it, I will change the fluid to..
Duct Tape Tech.
Joined: Jul 2009
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From: San Antonio Tx.
I found this on Red Line oil's web page it shows, Joe and Dave to be correct about too much Friction Modifier. I stand corrected, I guess I got some bad info SORRY
Limited Slip Friction Modifier by Red Line
Description: Compatible with petroluem or synthetic gear oils, Red Line's Limited Slip Friction Modifier will significantly reduce the friction break-in of differentials, reducing break-in temps by as much as 50 degrees. Limited slip or positraction units will often chatter without use of this product or a gear oil with a similar modifier, so add only enough to eliminate the chatter and avoid making the plates or clutches too slippery.
Limited Slip Friction Modifier by Red Line
Description: Compatible with petroluem or synthetic gear oils, Red Line's Limited Slip Friction Modifier will significantly reduce the friction break-in of differentials, reducing break-in temps by as much as 50 degrees. Limited slip or positraction units will often chatter without use of this product or a gear oil with a similar modifier, so add only enough to eliminate the chatter and avoid making the plates or clutches too slippery.