What's Going On With My Differential

Discussion in 'Transmission & Drivetrain' started by TheHydro, Jul 12, 2016.

  1. TheHydro

    TheHydro Well-Known Member

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    I took my diff out and took it to a reputable shop in town and had ford racing 3.31 gears installed and my 3.73s taken out. I provided them with the complete install kit. I picked up my diff and reinstalled it along with DSS 800 axles and put in amsoil severe gear. Everything has seemed fine for the first 500 miles or I just haven't noticed it until recently but now I'm hearing a single pop sound when taking off from a stop. Also when pulling in to my driveway my passenger side rear tire comes off the ground (caused by Bmr sway bar) and the tire in the air spins and the one on the ground doesn't move much and the car makes a shuddering sound from the Rearend. I usually let the car roll back and get at a better angle where both tires on in the ground and pull in to the garage. What is going on with the diff?
     
  2. GTBOB

    GTBOB Well-Known Member

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    Being that you have a Torsen diff, they require more of a torque differential for it to lock. Very small amount of torque is being generated when you creep up the driveway. The Torsen has a torque bias ratio of around 3:1. If the low traction side has 0 traction, the high traction side gets that amount x3...which is still 0. ;)

    Try this next time. Pull the emergency brake slightly up when you get the one wheel off the ground. This will send additional torque to the other side:thumbsup:. Audi's have been doing this electronically for years!
     
  3. OP
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    TheHydro

    TheHydro Well-Known Member

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    Thanks for the help, that makes sense.


     
  4. Cobrakev

    Cobrakev Well-Known Member

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    Can I ask what they charged you for gear swap?
     
  5. OP
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    TheHydro

    TheHydro Well-Known Member

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    It was $320 for the labor to swap the gears.

     
  6. EXP Jawa

    EXP Jawa Well-Known Member

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    Basically, the Torsen in your car has no preload springs, which in turn improves its turn-in feel. But if you jack the rear of the car up off the ground and turn one tire forward, the other with turn backward. You need to maintain some reaction torque on both outputs for the differential to operate correctly. Usually that reaction comes from the tire contact with the ground, but can come from the brakes. Sometimes traction control will help that, but the bottom line is that you need to keep your tires on the ground!
     
  7. whatsup62

    whatsup62 Well-Known Member

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    I have DSS 800 shafts and Amsoil severe gear in as well. PP car with 3.73's. I have the pop as well since putting in the axels. I was told to loosen axle nuts then retorque...still has the pop. Mine happens when first starting out and on narrow turns. Once car has been driven for a bit it is not as noticeable.
     
  8. OP
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    TheHydro

    TheHydro Well-Known Member

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    Thanks that sounds like exactly what I am hearing.

    QUOTE=whatsup62;1386343]I have DSS 800 shafts and Amsoil severe gear in as well. PP car with 3.73's. I have the pop as well since putting in the axels. I was told to loosen axle nuts then retorque...still has the pop. Mine happens when first starting out and on narrow turns. Once car has been driven for a bit it is not as noticeable.[/QUOTE]
     
  9. Mikeg4572

    Mikeg4572 Well-Known Member

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    Mine has the same noise after the DSS 800's. Drove me crazy at first. I thought I did something wrong. I double checked all my work and then event took it to a shop to triple check all my work. Everything was done correctly.
     
  10. EXP Jawa

    EXP Jawa Well-Known Member

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    Are you saying that it makes one, single, pop noise when entering a turn? Or does it do it when you are in straight (or near straight) line? If there's a noise coming out of the differential when turning, I fail to see how retightening the axle shaft nuts on the outer end would impact that. If it starts/stops with a turn, then its driven by something that only sees relative change when turning - like gearing or some other part within the differential itself. Unless I'm reading this wrong. If it occurs when going straight, however, it could be attributed to a lot of things - but not the differential.
     
  11. Mikeg4572

    Mikeg4572 Well-Known Member

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    Mine seems to do it when starting forward or reverse in a straight line. Almost as if the new shafts are ever so slightly smaller and are moving just a little in the hub. I stopped worrying about it as I have several 5500 rpm launches on it and no issues.
     
  12. EXP Jawa

    EXP Jawa Well-Known Member

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    If its straight line, then its not in the differential itself. It has to be something that is either inputting torque to the differential, or output from it (like the upgraded shafts) making the pop. But despite this thread's title, the differential itself (ie, the Torsen unit) can't be contributing to a noise in a straight line as its internal parts have no relative motion when going straight. I just wanted to point that out.
     
  13. wildcatgoal

    wildcatgoal @sirboom_photography

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    I get pop and sometimes a rubby sound after lowering the car with springs/shocks, adding bracing, sway bars, adding in the Steeda IRS stuff. Everyone is installed properly, torqued. I plan to jack the car up and clock all the bushing bolts (loosen, re-torque with weight on the car) when it goes in for another alignment (not happy with current one). Also have the goofy Torsen noise experience which is kind of embarrassing when someone else is in the car, but whatever.
     
  14. EXP Jawa

    EXP Jawa Well-Known Member

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    Goofy Torsen noise experience?
     
  15. wildcatgoal

    wildcatgoal @sirboom_photography

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    ^The goofy Torsen noise experience. :lol:
     
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