DIY Perrin Rear Differential / Subframe Lockdown System
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This is a discussion on DIY Perrin Rear Differential / Subframe Lockdown System within the Suspension and Handling forums, part of the Tutorials & DIY category; Adding the PERRIN Subframe Lockdown System adds rigidity and stability to the rear end diff. This kit eliminates all driveline ...

  1. #1

    Join Date
    Feb 2008
    Hillsboro, OR

    DIY Perrin Rear Differential Subframe Lockdown System

    Adding the PERRIN Subframe Lockdown System adds rigidity and stability to the rear end diff. This kit eliminates all driveline slop and the annoying thud that can be heard shifting from first to second. The results can be felt the first time you take off from a stop light at almost any speed. I have to say that this has to be one of the best “bang for your buck” mods I have ever done. For more information click here.

    Needed tools:
    1) 12mm socket or wrench
    2) 17mm socket or wrench
    3) Jack and Jack stand

    Step 1) Raise the vehicle to a desired height allowing you enough room to move freely. For this you will want to use jack stands to support the vehicle while working on the cross support. NEVER WORK ON A VEHICLE SUPPORTED ONLY BY A JACK.

    Step 2) Time to remove tension from the differential, this will allow you to lower the differential stabilizer. You’ll need to get a floor jack for this next step. Placing the jack under the differential you’ll want to raise the differential roughly .5”.

    Step 3) Using a 17mm socket remove the 17mm nuts securing the differential to the cross support. Remove the studs from the differential and the cross support by using the “Jam-Nut” method. (this is where you “jam” two 17mm nuts together on one stud. Then you can remove the stud by unscrewing the nut closest to the differential). Repeat this process on the remaining stud. If this method doesn’t work you’ll have to use a stud-extracting tool.

    Step 4) Once the two studs are removed from the differential and the cross support you will remove the two 17mm bolts and nuts securing the differential stabilizer to the rear sub frame. Its now time to lower the differential, you will only need to lower it slightly to allow for clearance. If needed you may want to remove or lower the exhaust system allowing your self even more working room.

    Step 5) Remove or lower the differential stabilizer from the sub frame. After you have done this you can install the 4 smaller red urethane bushings around the OEM Bushings center mounting points. (2 bushings installed on each side)

    Step 6) After all 4 of the PERRIN bushings are in place you can now reinstall the differential support brace into the chassis. (Don’t fully tighten just yet)

    Step 7) Raise the differential back into the car, line up the stud holes with the differential support holes and reinstall the studs.

    Step 8) Tighten the differential stabilizer support bolts to 70ft-lbs. Now go back and tighten the nuts on bolts on the sub frame to 70ft-lbs.

    Step 9) Time to install the rear sub frame lock out bolts. You’ll want to locate the empty threaded holes on the rear sub frame. Screw the bolt and bushing into the empty hole on each side of the car. Tighten the bolts down to 60ft-lbs. (BOLTS AND SPACERS MAY MAK SOME POPPING SOUNDS WHILE THE BOLTS ARE BEING TIGHTENED INTO THE CHASSIS, THIS IS NORMAL)

    Step 10) Locate the differential front support beam and the 2 outer bolts securing it to the chassis. Remove the passenger side large bolt securing the front support beam to the chassis, and the two bolts securing the plate to the chassis.

    Step 11) Pull down the front support brace until there is enough room to place the new bushings on top of the OEM bushings.

    Step 12) Reinstall the plate back onto the chassis and tighten the 12mm bolts to 25ft-lbs. Install the large 17mm bolt through the bushings and tighten to 100ft-lbs.

    Step 13) Repeat step 10, 11, and 12 on the drivers side.

    Step 14) Lower vehicle and test drive.



    Last edited by PERRIN_KEN; 09-23-2008 at 12:19 PM.

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  3. #2
    Registered User
    Join Date
    Oct 2008
    Hillsboro, OR
    The subframe lockdown system will give you great feel for the rear of your car, and give you a lot less deflection! A great mod for little money and effort!

  4. #3
    Registered User STI_KLR's Avatar
    Join Date
    Dec 2007
    The taint of Northern Virginia.
    I got mine on Monday!

    Too bad I don't have a lift, jackstands, etc here at school to install them
    Rogan: Live simply, love generously, care deeply, speak kindly.
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  6. #4
    Registered User
    Join Date
    Mar 2010
    Woodland Park, CO
    I just finished installing these today. It went pretty well, though I thought I'd post a few tips from my installation:

    I backed the car up onto ramps instead of using a jack and jack stands, worked fine. You'll still need a jack to support the differential.

    You'll need more tools than the ones listed, due to limited access to the differential bolts and nuts. I used a deep 17mm socket for most, but also need a 17mm combo wrench.

    I used the 'jam nut' method to remove the two studs, using the 17mm nuts removed from the outer bolts here. First back the stud's 17mm nut out far enough that an open end wrench can get to it from the rear of the subframe (you'll use that to remove the stud). Then install that extra 17mm nut, snug it down with a socket, and you're good to go. Once the stud is removed from the differential cover, leave the nuts on the stud as you'll use them to later reinstall the stud.

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