Hi guys, I am just going to give a write up on the 50/50 powertrack insert install. This is a guide if you are looking to move to 50/50 torque split full time on your Quattro system, instead of the 90/10, 70/30 from the factory. I had trouble finding any guides online which made it frustrating for me, at one point I thought i was going to have to pay a mechanic to drop Mr. Haldex down enough. It's actually really simple! This guide will cover the circlip insert as well as the 17mm hex bolt. They are in the same location, however for MY 2002 and above, they use the circlip (Like mine). Please double verify which insert you need before buying. There is a hex head bolt at the top of all Haldex units, what you need to feel/look for is directly on top of the controller, not the rest of the Haldex.
***I ONLY RECOMMEND THIS MOD IF YOU CANNOT AFFORD A NEW CONTROLLER LIKE ME, AND IF YOU FOLLOW ANYTHING FROM MY GUIDE YOU ACCEPT FULL RESPONSIBILITY FOR ANYTHING THAT GOES WRONG, IF ANYTHING GOES WRONG. IN OTHER WORDS, I AM NOT LIABLE***
Please browse through the attached photos first, as well as read the full guide before performing any actions.
So first off you will need to identify specific parts and their locations. Once you have your vehicle on jackstands, a lift, whatever, look at the rear differential. at the front, you will see a small screw for draining the Haldex coupling oil. I recommend changing the oil, especially if you do not know the last time it was changed, like me. There are plenty of guides online. At the rear of the diff, you will see two bolts holding a cover with wire plugs attached. This is where the Haldex Controller can be unplugged for removal. Now, at the front, right, upper side of the diff you will see the words Haldex. That is the Haldex controller location, and the item we will be removing to install the powertrack insert. In the pictures below, you will see where the two bolts mount the controller to the haldex unit.
If you plan on a Haldex oil change (PN G 052 175 A1) please first drain the oil, as you will lose some oil upon removal of the controller. Do not lose the plug or it's washer. Some oil change kits come with a new plug and washer (I recommend getting a new one)
While the oil is draining, you can remove the two bolts (8mm hex head?) holding the electrical plug for the haldex controller and unplug it, use minor force to not break anything, I used a small flat head screwdriver to unlock the plug. The end going to the controller will be on the right side, and on the top of the differential will be clips holding the wire harness down. You will need to apply a minor bit of force to remove the wires from the clips. Verify that the wire is completely loose by lightly pulling the wire from the end at the controller. Keep in mind the wire may get caught up on whatever in the tight space. Leave the wire on top the the differential to compliment the lack of space around the controller.
Once the oil has finished draining, do not fill the unit with oil yet. reattach the drain plug to keep excess oil from dripping all over you while you remove the controller.
I failed to get a photo for this step. In this step you will remove the gas tank brush guard/shield. I believe there is three push on clips that need to be removed plus two nuts. the push on clips are removed by pushing the bit of plastic holding them down off, then using a flathead screwdriver to half screw them off and half pry them off. Remove the other two nuts. (there might be more, however thats what was on my TT)
Study the 6th photo below, the picture of controller in my hands. Take note of the locations for the bolts attaching the controller to the rest of the haldex unit. Unplug the precharge pump from the controller (photo 7). I used a small flathead screwdriver to unlock the plug and a large flathead to assist in prying the plug out. once the plug is out you can rotate it down and out of your way.
Using a 4mm allen hex wrench place the long end into the lower bolt. I had to use a pair of pliers to turn the allen wrench to loosen the bolt. After that the bolt should be loose enough to use just the allen wrench to remove. Place bolt in safe location. With the upper bolt, I had to use a small rachet and 4mm hex bit to remove. First place the bit into the bolt, it should hold. Carefully place the ratchet and socket over the bit and loosen. Once it is loose, you can just use the bit to spin the bolt off. Congratulations! You can now remove the controller. It will take a bit of rotating to remove, and don't forget to feed the wire harness. You may have some oil drip upon removal
Once the unit is out you can now remove the c-clip (DON'T LOSE THE C-CLIP!!!!!!) or the 17MM hex bolt. If you have the circlip model, once the c clip is out, use pliers to pull the plug out. At this point in time, I cleaned the whole controller, removing excess dirt and grime. To install the circlip insert, I placed it into the hole and did my best to get it in as deep as possible. I had to use the end of a hammer to tap the insert in all the way. Please be careful, as this whole unit is aluminum, which is soft. Place the c-clip back in place, and pull the insert up all the way until it meets the c-clip. IF you have the bolt insert, DO NOT crank it two turns past tight, as you may end up pulling threads. Make it tight, but go easy. Store the old insert in a safe place, you might not like the new insert.
At this point in time the insert has been installed into the controller. You may now begin reversing steps to complete the whole install. Remember to go easy and do not force things. If you have to apply a lot of force, put whatever it is into a new position, as things may be misaligned. When tightening bolts, remember that everything is aluminum and you can easily ruin threads when tightened too much or if you do not align the bolt into thee hold properly. Once the controller is reinstalled, all the electrical plugs and reconnected and bolted down if need be, you may continue the oil change. It may be easier to change the oil filter while the controller is out. Remember the filter requires a special wrench. once the filter is changed, you can remove the oil drain plug and fill the unit. Have the (new?) bolt and washer ready to install before you fill the unit as you want to lose as little fluid as possible.
Verify that everything has been completed. Once everything is completed, you may test out your new 50/50 AWD! You can also add a toggle switch to the Haldex controller so that you can determine when you want to be either FWD or AWD. That is done by adding a switch to the 12v power. An easy way to tap into the 12v power is through the fuse box.
If you feel no change whatsoever, scan block 22 (AWD) via VCDS. If you see a code 01155, you are in the same boat as me. The likely culprit is the precharge pump, in which either it has failed or is failing. I have a new pump on the way.