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Thread: LSD Help

  1. #1
    Join Date
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    LSD Help

    Last summer I purchased a used carrier from MustangEddie, because my spider gears were shot, and had a local shop install new carbon fiber clutches along with new axles, and axle seals. I provided all of the parts and soaked the clutches in friction modifier.

    Shortly after I got the car back, I jacked up the left rear and was able to turn the left rear wheel/tire with a little bit of effort. I thought I read that it should take about 200 ft/lbs of torque to break the LSD loose?

    I run several auto cross events each year and I'm still spinning the unloaded wheel around corners.

    Is it possible to install wider discs or a stronger spring to tighten up the LSD?

  2. #2
    Join Date
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    I think justbob put in a F150 S spring. He should confirm or deny.
    Last edited by RubberCtyRauder; 11-25-2021 at 02:28 PM.
    2004 SB Ported Trilogy 48
    Has supporting mods and stuff
    Thanks to Marty O for his help in updating this car.

    R.I.P.
    Rex "SC Cheesehead"

  3. #3
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    LSD Help

    In my opinion the more both wheels grab also increases your chance of whipping a 180.

    I NEVER give my MM throttle around a wet or even damp curve/turn until straight, it would not end well, and never more than 1/4 throttle at most on warm dry pavement powering out of even he slightest curve. My F150 has open diffs and never once has the rear end broke loose unless the weight of the truck pushes me sideways from aggressive driving. With 4WD I have plenty of traction when needed and I would never want limited slip on it as we get decent snows here. Itís a great feeling of safety and nerves when Iím good and used to the unpredictable car.

    With the old Trilogy and only 461 HP I had and plenty of loonngg burnouts along the way the carbon clutch packs never failed to last 40,000 miles. You could pretty much set the clock on the next embarrassing one tire fire.. I honestly canít recall how much force it took to spin one wheel lifted. The concern is really more how much it takes to stop it from turning when the pinion is spinning it.

    There really is nothing else you can do besides a diff upgrade. A new standard size spring will work wonders. No matter how hard an old spring is to install, obviously springs wear. Iím not at all a fan of crushing an F150 spring to fit like Iíve read over the years, plenty have done it, but I never saw the purpose. You completely change the characteristics of the springís design the second you alter it and every tiny fraction will yield itís effectiveness of design, to me itís common sense physics, but thatís just my opinion.

    Like I said, never an issue lasting a good amount of time on decent power, decent street tread, rarely on stickies, regular old Motorcraft fluid with modifier, cobra clutches, and a new stock spring. Honestly I got the same mileage out of the stock clutches before boost even.

    But who am I besides another internet opinion? Go with your gut.


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  4. #4
    I would think that slightly thicker clutch pack washers (for example .040 vs .030 thickness) and a new spring (not an F-150 one, I have no idea how people get those to fit) would help you quite a bit.

    I'm rebuilding mine now with factory style clutches but I got a new S-spring and I'm using .30 shims where the ones I am taking out were around .25 or less. It should tighten things up nicely.
    Last edited by Prospect62; 11-27-2021 at 07:38 AM.
    2003 Marauder 300A | Stock with 306,000 miles and counting

  5. #5
    Join Date
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    Thanks for the help. Where is a good place to buy the thicker washers and spring?

    Here's a video where when making the wide sweeping turn, I'm typically spinning the unloaded wheel.

    https://crouse.smugmug.com/DCTC-5-23-2021/i-HpRZLpT/A

    Thanks,
    Curt

  6. #6
    Join Date
    Dec 2018
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    LI NY
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    Quote Originally Posted by crouse View Post
    Where is a good place to buy the thicker washers and spring?
    Thanks,
    Curt
    A trick I learned in my fox body Mustang days is you can remove one of the steel plates from the clutch kit & add an extra clutch plate on each side which ends up giving it a bit more grip. The different thickness shims used to come with the new clutch kit. Have plenty of extra shims here if you need lmk.

  7. #7
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    I just remembered that I still have the clutch set from the differential I bought from you. I'll check to see if I can find two plates that are still ok.

  8. #8
    I referred to them as washers but the actual name for what I’m talking about are shims, specifically Trac Loc shims. I looked in the usual places like eBay and Amazon and couldn’t find any. The Ford M-4700-B Trac Loc rebuild kit that I bought came with a nice assortment but outside of buying that whole kit, this is the only place I could find that sold just the shims…

    https://www.diffsonly.com/FORF880730...d_p_10847.html
    2003 Marauder 300A | Stock with 306,000 miles and counting

  9. #9
    The part number for the S-spring is EOAZ-4214-A. They’re going for around $28 on eBay.
    2003 Marauder 300A | Stock with 306,000 miles and counting

  10. #10
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    Rosemount, MN
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    Thanks again for the help.

  11. #11
    Join Date
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    APPLE VALLEY,CA
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    That's one reason I decided to go with a Eaton Detroit Tru-Track when my Right Axel Seal blew for the third time and took out the gears.
    I upgraded to 31 spline axels at the time.

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