S-Runner TrueTrac Install Write up

[heloboby7]

So I decided to make a contribution to the Tacoma community. Isn’t that good? All modifications were performed on a 2001 Tacoma S-Runner.


Tools needed:

Shop press
10mm wrench
12, 14, and 17mm sockets
Air tools are preferred but not necessary
Dial indicator

The first thing that needs to be done is to clear an adequate work space and get all your tools, jacks and jack stands in order. Once that is done, put the truck in the air and secure it with jack stands. You will want to get the truck pretty high up so you have some space to work with.



Take off the wheels and the brake drums (make sure the parking brake is NOT set).

[heloboby7]

Next, you will want to take off the rear section of the drive shaft. Before you do this, get a paint pen or some white out and mark the orientation of the driveshaft in relation to the pinion flange on the rear end and the front section of the drive shaft.



As you can see, I made dots on the bottom side of the driveshaft where it connects on both ends. If you do not do this, you may have vibration issues due to the driveshaft being out of phase. Take out the 12mm bolts and nuts on either end of the rear driveshaft section and wiggle it out.





With that out of the way, go ahead and drain the rear end. Before you pull the drain plug, pull the fill plug. You do not want to have an empty rear end and end up stripping out the fill bolt. Both are 24mm bolts.

[heloboby7]

After your rear end is drained enough to your liking, pulling the axles is the next step. Unbolt the parking brake cable from the drum brake assembly (10mm bolt), reach down behind the brake shoe and pop the end out of the cable bracket. It may take a little bit of effort. Pull the cable out the back of the drum assembly and set it off to the side. Loosen the brake line with a 10mm wrench or line wrench, pull it out and let it hang. It will leak out a lot of fluid. You will see on the back side of the drum assembly, where it is bolted to the axle housing. There are four 14mm nuts.



Remove those and pull the whole axle and drum assembly COMPLETELY out. Do not just pull it out a little bit and let it hang. It will ruin your axle hub seal. Repeat the procedure for the other side.





You can now remove the ten 12mm nuts that hold the 3rd member to the axle housing.



Being very careful, slide the 3rd member off the studs and out of the housing. The third member is awkward and heavy so don’t be surprised when it falls and smashes your finger or head.

[heloboby7]

You can now prep the TrueTrac. Bring your new carrier bearings (90366-51001 for 8.4” rear end) and differential to the press.



I used an appropriate sized socket that matched the diameter of the inner race of the bearing to press it on.



Make sure the bearings go on straight and all the way down with the large end of the taper closest to the inside.



Now back to the 3rd member- Make a clean work area for yourself and move the differential to it. Attach the dial indicator to a sturdy base with the tip of the indicator on a tooth of the ring gear.

[heloboby7]

Gently rock the ring gear back and forth to measure the stock lash amount. My stock lash amount was .003” as shown.





Write that down or remember it. Next, take off the four 17mm bolts that hold the bearing caps and set them to the side.



Pick up the stock differential and set it to the side.



Make sure you remember which shim went to which side.

[heloboby7]

Remove the twelve 17mm bolts from the differential that hold the ring gear and slide the ring gear off. You may have to tap it with a rubber hammer every now and then to get it all the way off.





Make sure the ring gear mating surface on the TrueTrac is clean and put the ring gear on. It is a very tight fit so rotate the ring gear and slide it down straight to find the best fit. I got the ring gear down as far as I could and I threaded in a couple of the bolts. I marked the bolts with a paint pen and used them to slowly draw the ring gear on the rest of the way.



When it is fully seated, install and torque the rest of the bolts using a thread locking liquid.



Now, test fit the TrueTrac with the stock shims. If your differential is like mine, it will not fit as the machining tolerance on the new differential does not match the stock one. I had purchased a few different thicknesses of shims from the dealer before I started and I would recommend doing the same for your project. I ended up using the stock shim on the end opposite the ring gear and a slightly thinner shim on the ring gear end. This would bring my lash measurement to .006” which is still within factory specifications.

Each time you try a new shim, you have to bolt on the bearing caps, torque them, and recheck lash. Once your lash setting is to your liking, make sure everything is torqued and begin reassembly.



Install the 3rd member back into the housing using a new gasket. Reassemble everything else, fill the rear end with fluid, bleed the brakes, then go leave a couple of black marks on your favorite local street (I do not condone exhibition of speed on public streets). The job took me a total of 2 hours to complete.

[voodootrip]

Very nicely done

[dropthattaco]

Fantastic writup! Isn't having two wheels driving great?!?!?

[Chris D.]

needs to be added to the FAQ ASAP!

I now know what I need to do to swap in my 3rd member..
I'm a pictures kind of guy

Question;

1. What did you use for the gasket on the 3rd housing?

2. Did you replace the end seals on the axle?

3. Is there anything you could do to prevent a lot of brake fluid loss while doing this?

4. Torque specs for everything removed/installed?

5. Any tricks for the rear ebrake removal? I looked at it a while back.. can't remember whats what..

[voodootrip]

needs to be added to the FAQ ASAP!

Noted and nominated