Tech Article Title Author Date
UUC Audi Driveline Stabilizer Don Pavlik 2000

I heard lots of positive comments about the UUC Audi Driveline Stabilizer (ADS henceforth) so I decided to get my S4 one for her birthday (Oct. 12).  Since I didn't want to make her wait to open her present (birthday falls mid-week this year) I gave it to her early so we could install it right away.

The ADS is a stout piece of hardware with heavy plate steel ends with a beefy center section.  Looks well made and it's finished well enough for a piece that will forever live under the car.  As usual with everything I buy I was short one piece of hardware (one washer).  Took me about an hour to install since I was doing it on ramps, taking pictures and making mental notes.  Actually, I spent more time getting the car up on my ramps than I did on the actual install. My ramps provide 9.5" of lift but the approach angle of the ramps is so steep that the nose of the car hit the ramp before the tire was within 4" of the ramp. Damiiiiit. I had to add on to the ramps with some 2x8s to get her up in the air. In case you're wondering, the wood add-on is secured with 3/8" bolts to the ramp itself so nothing moves.

Getting the car on ramps proved harder than the ADS install

The difference in the feel of the car is pretty amazing.  Gone is the slop in the driveline I normally experienced while creeping along in traffic while in 1st or 2nd gear. Before installing the ADS if I lifted off the throttle in 1st at about 2,000 rpm the car would yo-yo (Car and Driver called it "rubber banding") while the mass of the car and the torque of 1st gear fought each other. Btw, this yo-yo feeling is not unique to the S4... most other cars do the same thing.  IMO, the reduction of just this annoying behavior makes this mod worth the price all by itself.  Other benefits are crisper, more positive feeling shifts and a more positive feeling when letting out the clutch quickly.  

The only downside I see at this point is an increase in driveline noise transmitted to the interior and a vibration that can be felt in the floor if I hold the engine around 4,000 rpm. I checked the alignment of everything and verified that the exhaust was not hitting on the center brace (it's very close on the passenger side) but all looks good. I guess if everything is held more secure a little more noise is to be expected -- not a big deal, just an observation. My only other issue is that the brace would probably  prevent the transmission from tilting down and away in the event of a front end collision -- may not be an issue, dunno.   

UUC documentation is good but pictures would have been nice.

I suspect other performance vendors will soon offer an ADS type of brace of their own if they have any common sense... nice modification.

The Install

  • The mount of the ADS attaches to a mount point that, strangely enough, already exists on the transmission.  
  • Mount in place.  Install nearly 1/3 of way done!  
  • The only part of the install that my give some people pause is removing the bolts that secure the engine cradle.  
  • Per the instructions, I used a piece of wood (2x8x3') and used a jack to support the engine before removing the cradle bolts.
  • Engine supported, you loosen the 3 bolts that secure the cradle. 18mm and 13mm socket needed.
  • All that black goopy stuff is cosmoline the factory sprays on the bottom of the car for corrosion protection.
  • Next, you put the ADS in place along with the aluminum spacers. 
  • Put the big spacers in place before putting in the smaller bolts or there is not enough clearance to squeeze them in.  Damn the ADS is heavy when you're laying on your back putting it in place for the 2nd time. : )
  • Exhaust to ADS clearance is very tight on the passenger (RH) side but I don't have any contact.  See update below.


  • The whole assembly doesn't hang down much lower than the exhaust itself. 
  • View from the front of the car


After some driving around for things to settle in and more aggressive driving I found that the RH section of the exhaust was hitting on the bar.  This was very obvious as a noise resonated through the car.  The instructions mention if you have a clearance problem to install additional spacers between the transmission and the new mount.  I put in an extra pair but it it was not enough to solve the problem. Putting an 2nd pair would have put the transmission and the bar under constant tension once everything was tightened down. I contacted UUC but their comment was just additional spacers.  Hmmmm, not possible.  After some more fiddling I decided to "make" room by putting a chamfer on the back edge of the bar where clearance was tight.  See updated installation instructions below that should eliminate the need to do any modifications to the bar.  

  • The point of contact (no, this isn't a Sprint commercial).  The exhaust was contacting the bar.
  • My solution was to simply "make" some room since the bar is solid bar stock.  10 minutes with a dremel tool and some touch-up paint solved my problem.

Revised Installation Instructions

How to properly install the ADS. (courtesy of Richard Hameroff)

This installation should really be performed on a lift. It should be mentioned, that the ADS brace itself is perfectly produced, but the provided spacers were made too short by the machine shop. This FAQ will in detail, explain how to make a perfect install, with the provided hardware. In addition, you will need (4) " max washers, and about (20) 3/8" min washers.

(1) With a 2X4, support the rear of the engine cradle under the rear engine mounts. The 2X4 should be long enough to cross the span between the mounts (they look like round silver caps). With a jack stand, put enough pressure on the 2X4 to begin to raise the front of car off the lift pads.

(2) Remove the large green headed bolt, and the two smaller bolts that hold the triangular silver plate at each side of the vehicle (rear sub frame bolts) The silver plates will not be needed anymore, so put them, as well as the old mounting hardware in a safe place.

(3) Install the trans mount with the provided hardware onto the two empty threaded holes on the bottom of the transmission. Just lightly snug it in for now, so it can be adjusted later.

(4) Using the new provided hardware, place a washer over the large bolts. Insert the bolt through the large hole on each end of the ADS. Then, place two of the " max washers on the large bolt (after you have inserted it through the ADS) then one of the provided large aluminum spacers. Do the same on the other end of the ADS.

(5) Now, lift the ADS into place and thread the bolts in until it just becomes snug.

Put one of the provided washers on each of the two smaller bolts, insert them through the two smaller holes on the ADS.
The smaller provided spacers need to go in between the ADS and the body, and the additional 3/8" washers are used to fill the void that has been created by adding the two larger washers on each side. Put in enough 3/8" washers until there is no clearance remaining between the ADS and the body. Repeat this on the other side.

(6) Torque the large bolts to 125 ft/lbs. Torque the smaller bolts to 15 ft/lbs.

(7) There will now be a small space between the newly installed trans mount, and the ADS center plate-mounting hole. Without putting any upward or downward pressure on the transmission, fill the space with enough 3/8" washers to fill the space. Insert the center transmission-mounting bolt through the ADS, into the trans mount. Again, the washers go in between the ADS and the trans mount.

The idea here is to make sure when you tighten the center trans mount bolt, that you are not pulling the transmission down in the process. The transmission must remain lax to be perfectly aligned. This is one of the most important steps.

(8) Tighten the two trans mount bolts on the transmission to 15 Ft/lbs, and the center bolt to 20 ft/lbs.

(9) At this point you are done, and there should be ample clearance from anything that can cause vibration.

Enjoy, (you will!). Richard Hameroff

PS, if your mechanic has ANY questions, just have him give Richard a call at 518-434-4077