12-15-2007, 01:03 AM
Join Date: Nov 2007
Location: Hillsboro, OR
DIY Perrin Rear Differential / Subframe Lockdown System
As some of you may or may not know, we here at PERRIN have taken on a little project called Project $15K. This is where we take a 2002 WRX and build the ultimate daily driver. After washing it and cleaning everything up it was time to change out all of the fluids. While doing this we decided that we should install our SLS.
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.
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. Make sure to install bushings between steel flat washer and OEM bushing.
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.
1-503-693-1702 Ex. 113
Last edited by PERRIN_Ken; 12-15-2008 at 03:31 PM.