TA Performance Girdle/Fluid Installation

Tools and parts you will need:
Floor Jack
  • Jack stands
  • 13 mm socket
  • Ratchet
  • Torque wrench
  • 1/4" Hex end socket
  • 3/8" Hex end socket or wrench
  • 22 mm or 7/8" wrench
  • Shop rags
  • Catch pan
  • 1 Gasket (comes with TA Cover)* or Red RTV Silicone Gasket Maker**
  • 2 quarts of Synthetic Gear Lube (Mobil 1 75w-90)
  • 1 bottle (12 oz.) of genuine GM limited slip additive***
  • Expect approximately 30 minute – 90 minute install time
    *  You can get a gasket at your local dealership or auto parts store.
    ** We used the gasket the first time and spotted a leak.  We redid this install using red RTV sealant.
    ***  The Torsen unit does not require the additive but the Auburn units do.
    Our car has the Torsen and we use the additive anyway.
    Date:  March 4, 2000
    Car:  1999 Z28 Camaro, 9,820 miles
    Installers:  Eric and Kelly Barger
    Email:  help@installuniversity.com
    People who helped us from major tech talk to general advice:
    • Jack (Jack98SS)
    • Steve (Java)
    • eboggs_jkvl)
      Elmer Boggs (
    • All my buds at LS1.com
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    Perform all these installs at your own risk.  Know how to use all of your shop equipment and take necessary safety precautions when performing ANY modifications and or maintenance items to your vehicle.  Seek the advice of a paid professional and do not substitute this publication for the advice of a paid professional.  This product is how we accomplished our installs and is not meant to be carved in stone.  We are not responsible for a mistake, misprint, or any other error found in this guide.  This guide is intended as a supplement and not to be your only source of information.
    Purpose:  The TA rear differential performance cover serves a number of helpful jobs.  You can fill and drain your rear differential fluid in a fast and convenient format (from the fill and drain plug).  They also claim that the cover will strengthen your rear end.  The last reason is because it looks good!
    1. We placed the rear of the car on two jack stands and chocked the front two wheels. We then let the floor jack down and moved it back out of the way. You should then find your rear differential housing cover and 10 bolts that hold the cover on (see the red arrow in Figure 1).
    Figure 1
    2. You will need to place some kind of catch pan underneath this cover before you begin to take the bolts out. Simply grab a 13 mm socket and ratchet and take the bottom bolts off. You might begin to experience some rear differential fluid to start to drain. Don’t worry; you are going to make a mess no matter how hard you try so continue to take the bolts out working your way up the cover.
    3. Once you have removed the cover you might need to scrape the gasket off of the cover and the housing. You can use just about anything to scrap the gasket off of the housing, a putty knife might work best. Before you lay the cover off to the side, look at the magnet and notice how much metal shavings you have on it. Do not be alarmed, you are going to have some shavings on the magnet regardless. Lay the factory cover and factory bolts to the side because you will not need them anymore, but be sure to clean them up after this install.
    4. You will need to try to get all of the old differential fluid out of the housing. So grab a shop rag and push it to the back (all the way back) of the housing soaking up all of the old oil you can. Do this for a few minutes to try to eliminate as much oil as you can.  We also used Carb Choke and Throttle Body spray cleaner to help get out the old fluid and to clean out the housing.  Just spray it liberally throughout the housing.  Watch your eyes!
    5. Once you have soaked up all of the oil you possibly can out of the housing, wipe the outside of the housing off where the gasket will go. Make sure you have the pre-load bolts (see green arrows in Figure 2) backed out of the cover so they do not hit the bearing caps when you place the cover on the differential housing.  Take a look at your bolts that came with the TA cover. You will notice you have 2 bolts that are longer than the rest of the bolts.  These bolts need to go in place where your brackets went (see black arrows in Figure 2).  Also be sure to use the thick washers with these bolts as well.  
    Note:  We removed the bracket on the left side of the housing.  The fit was not a very good fit so we just used a set of pipe wrenches to bend it so we could slip the wires out of it.
    Figure 2
    6.  You can either use a gasket or red rtv silicone gasket maker.  We used the gasket the first time and found a leak so we redid the install using the red rtv gasket maker.  So you can choose your poison in this step.
    A.  Get some Red RTV Silicone gasket maker material.  Red is the high temperature resistant and is a must for your rear differential housing.  Place a 1/4" bead around the inside of the cover.  Be sure to outline each bolt hole also with a 1/4" bead (see Figure 3).  Let the RTV air-dry for a good hour or until it doesn't stick to your finger when you touch it.  We  let it sit for about 45 minutes.  Be sure to remove any excess from the cover immediately because it will stain the cover.
    Figure 3
    B.  Line the gasket up with your TA Performance Girdle and place the girdle onto the housing. While you hold the cover and gasket up to the housing, line everything up so you have a clear shot to the bolt holes in the housing. Grab a bolt and get one started then grab another bolt and start it.  Don't forget to place the smaller washers in with the eight (8) shorter bolts and use the two (2) thicker washers on the two longer bolts.
    7.  We now want to go ahead and start tightening up the bolts (see blue arrows in Figure 4) to 25 ft-lb according to the installation instructions that accompanied the cover.  Try to tighten bolts on the opposite side of each other to get the best fit possible.  Just be sure not to over tighten.
    Note:  We could not fit our torque wrench on the two longer bolts because of the pan hard bar.  We raised the rear differential up enough with the floor jack so we could tighten them down to 25 ft-lb.
    Figure 4
    8.  We want to tighten the pre-load bolts to 5 ft-lb according to the installation instructions that accompanied the cover.  Our craftsman torque wrench did not have a setting that low.  We had to buy an in-lb torque wrench that was capable of making 5 ft-lb.  The first thing we had to do is figure out how many in-lb's does it take to equal 5 ft-lb so we would know which wrench to buy.  Let's use dimensional analysis to figure this out.
    So we bought a torque wrench that measured in in-lb and had 60 in-lb in its torque range.  Now we ran into another problem.  We have the torque wrench but we don't have a socket to fit the preload bolts.  The preload bolts have a female hex fitting in them to tighten them up.  To fix this problem we went to the local NAPA and bought a socket with a 1/4" hex end coming out of it (see Figure 5).
    Figure 5
    Now, tighten to the specified 5 ft-lb or 60 in-lb per the directions.  Make sure you pay extra attention during this step.  If you torque the preload bolts more than 5 ft-lb than you may cause damage to the bearing caps.  After you get the preload bolts tightened, you will need to grab a 22 mm or 7/8" wrench and tighten the nut on the preload bolts.  This insures that the preload bolts will stay put (see Figure 6).     
    Note:  We reversed the torque wrenches tightening direction while the wrench was tightening the nut.  This insured that the preload bolt didn't get any tighter.
    Figure 6
    Now if you ever want to just drain the oil just grab a 1/4" hex wrench and unscrew the lower plug (a.k.a. drain plug, see yellow arrow in Figure 7) and to fill, just use a 3/8" hex wrench on the upper plug (a.k.a. fill plug, see pink arrow in Figure 7).  Just be sure you do not pour more than 2.1 quarts of fluid in the housing if you use this plug.
    Figure 7
    9.  Go ahead and take out the factory fill plug located on the passenger side of the housing (see green arrow in Figure 8).  You will need to use a standard 3/8" extension to fit into the square hole.
    Figure 8
    10.  You need to fill the rear differential with the fluid.  The housing will take approximately (two) 2 quarts of fluid.  As we stated at the top of the install document we used the GM additive but there is no need to do this in a Torsen unit.  If you do use the additive you need to add it first.  Then you can add your choice of gear lube.  When the fluid starts to pour back out of the fill plug you know you have enough fluid in the housing.  You will need to tighten the plug back up.  We tighten it up pretty good but we don't pop any blood vessels doing it.  You do not want to over fill the housing.  It will leak fluid out from the vent tube on the top and possibly out the sides of the cover.
    There you have it!  Clean off the housing as much as you can and let the car down and go for a drive!  Keep an eye on your cover for some fluid leaks.  Mainly near the bottom of the cover.  You will have to visually inspect the cover up close to determine if you have a leak.
    Comments:  Once we filled the housing with the gear lube and additive, we felt that it was still easier to use the factory fill plug.  The factory fill plug is located on the passenger side of the differential housing.  We also noticed that if your car is placed on jack stands, the rear differential will hold over one (1) quart extra in the housing.  What does this mean to the average Joe?  You want to be sure to have your housing level when draining the fluid out or you won't get all the old fluid out.  Remember this statement for future use!
    Also, another reason to use the factory fill plug is that you can get a good idea of when to stop filling it up with fluid.  When the fluid starts to pour out of the factory fill plug you have just enough fluid in the housing.
    After having several weeks to check on the cover we have noticed some rear end gear oil on the bottom of the cover.  The drain plug seems to leak ever so slightly.  We do not find this to be a huge problem.  We just want to point this out so you can be ready to see some oil down there.  This seems to be a common occurrence with this cover.
    After finally getting a chance to reinstall the cover and measure how much gear lube came out of the cover.  We got a little over two (2) quarts of fluid.  So we can only conclude that we did not leak a massive amount of gear lube out and we might have overfilled the housing.
    Here is a shot of the completed job (See Figure 9)Just in case you are wondering, those are scrap pieces of "I-Beams"; we are pretty anal about safety.
    Figure 9
    Web Author: Eric Barger  help@installuniversity.com Copyright © 1999 - 2002  Eric Barger.  All rights reserved. Revised: June 07, 2007 .