COAL: 2013 Audi A8 L 4.0T Quattro – A Teutonic Chariot

A history of the A8

Audi has had an interesting journey in becoming the credible luxury brand that it is today. Its first foray into the vaunted large-format flagship sedan was a car simply called the “Audi V8,” which debuted in 1988 for MY1989. That car was also the first model to combine Audi’s Quattro AWD system with an automatic transmission. And while the V8 was a decent effort, many found it not quite posh enough to hang with the 7 Series and especially the S-Class.

In 1993, Audi debuted the next iteration of its large car—well, more of a preview, really. That concept was the ASF, which stood for Audi Space Frame. It comprised an inner cage made up of extruded and die-cast aluminum components, shod in unstressed aluminum body panels. Audi claimed a weight savings of 110 kg (242 lbs). To celebrate the car’s aluminum construction, Audi proudly displayed the unpainted, hand-polished body at the 1993 Frankfurt Motor Show. It looked every bit like the production version that was forthcoming. In keeping with Audi’s new nomenclature, that car was the 1994 A8, and like the concept, it was aluminum.

The 1993 ASF Concept.


The “D2” A8, as it was called, lasted from 1994-2002, and came in both short- and long-wheelbase body styles. It spawned a high-performance S8 variant in 1996 and a cheaper FWD variant in 1997. Between all the versions, there were four gasoline engines (2.8-liter V6, 3.7-liter V8, 4.2-liter V8, 6.0-liter W12) and two diesel engines (2.5-liter V6 TDI, 3.3-liter V8 TDI), each with multiple outputs. Horsepower across all the options ranged from 172 to 414.

The “D3” A8 began development in the late nineties and ultimately arrived in 2002 as a 2003 model. It was even bigger than the prior one, and boasted a number of high-tech accouterments, including Audi’s new MMI infotainment system. The cabin, meanwhile, was as modern as anything else on the market, and perhaps more so. It’s this A8 that brought the nameplate properly into the echelon of flagship world-class sedans, between the W12 version seen in Transporter 2 and the famous S8, with its 5.2-liter V10 engine. That V10, it should be noted, was used in cars like Audi’s own R8 and the related second-generation Lamborghini Gallardo and subsequent Lamborghini Huracán. The D3 lasted through 2010.

A 2004 “D3” A8, EU-spec.


And that brings us to the “D4” A8. It arrived in 2010 as a 2011 model and was an evolutionary redesign over the D3; I imagine non-Audi enthusiasts could mistake one from the other from some angles. Originally, for the US market, D3 A8 came with either the carryover 4.2-liter V8 (372 hp, 328 lb-ft) or an enlarged 6.3-liter W12 (500 hp, 461 lb-ft). Either one got you a new 8-speed automatic provided by ZF and standard Quattro AWD.

In 2013, Audi replaced the 4.2-liter with an all-new 4.0-liter twin-turbo V8 badged “4.0T”. Like so many engines nowadays, this was a “hot-vee” layout, meaning the turbos sat right in the valley of the engine, for shorter response times. In base form, this engine pumped out a staggering 420 hp and 406 lb-ft along with a zero-to-sixty time of under four seconds. The reintroduced S8 featured a hopped-up version of the 4.0T that put out 520 hp and 418 lb-ft. That same year, Audi also added a “3.0T” variant comprising, confusingly, a 3.0-liter supercharged V6 good for 333 hp and 325 lb-ft. In 2014, Audi introduced a “TDI” model with a 3.0-liter turbodiesel V6 also used by Porsche and Volkswagen. The TDI met an untimely demise after 2015, with Volkswagen Group’s famous “Dieselgate” scandal, but the other variants lasted beyond the D4’s 2015 facelift and through its discontinuation after 2018. With all models, you got Quattro AWD and four-corner air suspension.

A 4.0T long-block. Notice the turbos sitting right on top of the valley.

A Word on Audi’s Drivetrain Layout

Though Audi employs longitude-mounted engines, it does so in a rather odd way. Since at least the three-cylinder Auto Union cars of yore—and perhaps further back—Audi has placed the engine in the nose of the car, ahead of the front axles. Sitting behind the engine is the transmission, just as in a usual longitude arrangement…only it’s really a transaxle. Half-shafts come out of each side of the transmission, toward the front, and connect directly to the front wheels. This was why Audis were historically FWD. When Audi decided to introduce its famous Quattro system in the early 90s, it did so by directing output to the back of the transmission and to a locking central differential. That had output shafts that went both rearward (to the rear differential) and forward (to the front differential, contained within the bell housing).

In 1987, Audi replaced the original center differential with a Torsen-type differential. Ordinarily, this system was set up for a 50:50 front: rear split, but could apply as much as 80% of torque to a single axle as needed to improve grip. Still, even with this arrangement, the Torsen differential acts mostly like a limited-slip differential, which is to say that if one axle has no grip, the system won’t be able to supply a substantial amount of torque to the other axle. To address this, Audi first added a manually locking rear differential and then later electronic differential lock that could brake individual wheels to limit wheel spin.

The Audi “Ur-Quattro” transmission.


The overwhelming majority of Audi products have used this basic drivetrain layout, and either FWD or (more commonly) Quattro AWD. Likewise, other products have utilized the “Audi Layout” within the VW Group stable, up to and including the prior generation of Bentley Continental GT/C and Flying Spur. The latest incarnation of the Audi Layout is called MLB and is used on a number of VW Group products, like the A4-A8, Q5, Q7, Macan, Phideon, Touareg, Cayenne, Urus and Bentayga. Some of the newest MLB Ultra products can even disconnect the rear axle and go full FWD in unstressed, straight-ahead driving for fuel savings.

Audi MLB


What’s more, I suspect that this layout is part of the reason for VW Group’s “W” architecture, which is only just now being retired. The W engines are enabled by VW’s narrow-angle-V “VR” engine architecture, in which the two engine banks are between 10.5 and 15 degrees apart (as opposed to the usual 60 degrees or more). This allows both banks to share a head, but also means that they fit into spaces normally reserved for an inline four-cylinder engine. The 1997 Jetta GLX VR6 that was my 2nd COAL here is one such example, as that car had a pretty tiny engine bay and would otherwise not have had a six-cylinder anything. The W engines are basically two of these “VR” engines mated together on a common crank, at between 72 and 90 degrees of separation. For the benefit of the Audi-style cars, a conventional V12 would be too long to fit at the front of the engine bay like that, but a W12 is theoretically no longer than a V6 and so fits quite nicely. As it was, until the advent of the BMW M760Li xDrive in 2017, the VW Group large cars (A8, Phaeton, Flying Spur) had been the only ways to get a 12-cylinder and AWD in a sedan.

A bare 6.3-liter W12 block.


The idea of an engine forward longitudinal front- or all-wheel-drive layout is not unique to Audi. Other automakers (notably Renault and the Renault-derived Chrysler LH cars for FWD, Subaru for AWD and the Ford Transit for both) do something similar, but it’s worth noting here.

My Story

Alright, so with all that out of the way, let’s turn the clock back to June 2022. I knew I wanted something to replace the 2011 LS 460L, but wasn’t sure what that something should be. I can’t remember what I was looking at. It might have been X351-generation Jaguar XJs, which were the 2011-2019 model years…but then I saw a particular A8 on Facebook Marketplace at a local dealership, and the price looked right.

The A8, at the dealership.


I was able to confirm several things just from the pictures. I’m a size-queen, so if there’s a LWB version of a sedan, I want it. There’s no sense—to my eyes—in getting a SWB version of one of these cars when a bigger one exists. (It makes me very sad that the S8 was SWB-only in the US until 2019, when we stopped getting any SWB variant of the A8 at all). But this A8 was badged “A8 L” and therefore LWB, and indeed it did have the longer doors. It had the potent 4.0T engine. And, as evidenced by the radar on either side of the bumper and the “distance” toggle in on the cruise control stalk, it had adaptive cruise. It also had a couple of other desirable features, like the Sport appearance package, which got you the diamond-quilted seats that looked that much more upscale than the standard ones.

What a car!


I saw it late at night on a Saturday and resolved to look at it that Monday and did. I drove the LS there and the salesperson was all too happy to take a copy of my license and then send me on my way for a test drive. Compared to the LS, the A8 was every bit as classy as that car, but much lighter on its feet. The LS’s 4.6-liter V8 was down about 40 horsepower and was tuned to accelerate gingerly and reluctantly, but when you buried the A8’s throttle, it had a moment of brief lag and then simply took off. Despite being so nose-heavy, the handling was much better. While MMI looked intimidating at first glance—I had never used it—it was actually super easy, and all of the most frequent controls and actions fell readily to hand. The adaptive cruise worked great, bringing the car to a complete stop on the highway and then resuming with a light jab of the throttle. The only dumb thing was the monostable gear selector. Designed by ZF, the gear selector is incidentally the same one that was in my 2015 Grand Cherokee. It’s notorious for having difficult-to-sense detents and causing drivers to accidentally select the wrong gear. Unfortunately, the famous actor Anton Yelchin was killed by his own Jeep because of this faulty design.

The D4 A8’s ZF gear selector, as also used by the WK2 Jeep Grand Cherokee. Not a great design.


As for the car itself, I didn’t see anything wrong with it. The brakes, bushings and suspension all looked fine, and there were no obvious signs of an accident. Nor did the history report reveal anything odd. So, I went back and worked a deal. The dealership took the LS on trade, and I was on my way.

That night, I showed the car off to one friend or another and noticed the driver’s panel switches for the rear windows were broken. It would take more than one button press to roll the window up or down. And it seemed to be happening on both sides. That’s when I noticed the sunshades in the doors. I’m used to cars having dedicated switches for the sunshades, but Audi did things a little differently. The first tap would roll the sunshade down, and the second tap would actually roll the window down. And then the reverse when pulling the window switch up. So, it wasn’t broken after all.

The A8’s rear cabin. Isn’t that sumptuous?


Over the next few days, I noticed that the forward/backup sensors weren’t working at all. The overhead graphic that would normally be interposed over the reversing camera image and display a meter of how close objects were to the front or rear of the car was missing. And the parking-sensor on/off button didn’t do anything. Speaking of the camera, it had a defect that my prior white 535i also had, and I don’t recall if I mentioned it there. Essentially, at night, the camera would focus on the bright white reflection of the license plate lights on the bumper and would overly darken everything else, making the reversing camera mostly useless.

My first real test of the A8 was a trip to Houston, in which it did…fine. The adaptive cruise worked well in traffic, the A/C and cooled seats kept up with the 108-degree weather, the seats were all-day comfortable and had better massagers than the ones in the much-newer X5, and it even achieved 25 MPG on the highway and a full 540 miles of range between fill-ups. It would have been the ultimate road cruiser if it had been equipped with lane-keeping assist, instead of lane-departure warning that just vibrated the steering wheel, but it had hydraulic steering, so that wasn’t a possibility. (Audi added electric steering with the 2015 facelift, and with it proper lane-keeping assist, but mine was a 2013).

A few days after I got home, the A8 decided to have its first issue. I went outside and saw the right rear corner on the ground. Sure enough, when I checked it, I got a “check suspension” error and the compressor did not have any effect on raising that air strut back up. Well, off to FCP Euro. Fortunately, they sold a rebuilt version of the OEM strut. It was $600 with a $220 core charge. The problem was that the tower bolts for the strut were buried under a giant strut brace and a rather rigid wiring harness that I couldn’t seem to move myself. I had it towed to the Audi dealership, who was kind enough to use the strut I’d bought and install it for $200. While it was there, I had them check the non-functional sonar sensors, which were down to a wire that had dropped from behind the bumper and melted in front of the exhaust. I also had them do an oil change. The air suspension has had no issues since.

The A8 looking very sorry for itself, with one collapsed air strut.


The A8 handled several more trips to Houston with aplomb. I found it a very comfortable conveyance, and the ability to get all the way there (430-ish miles) and then still drive around town before refueling was nice. The X5 gets noticeably worse fuel economy on long trips, due to the 800-lb battery that’s not much help at those speeds.

My second issue, and it was a bit of a doozy, was when I started to hear a whistling noise near the top of the windshield. I was annoyed but ignored it for a few days. And then I went through the automatic carwash and saw water leak down from the top of the roof, just behind the mirror, and then come cascading down right on top of the MMI controls. To the car’s credit, it didn’t appear to damage anything, but it sure was worrying at the time. I took it back to the dealer, where they sent me pictures and told me what happened. Apparently, someone had replaced the A8’s windshield at some point. They’d purchased the OEM one, but didn’t remove all of the old sealant, so the new windshield didn’t seal properly and eventually came loose. They said they could try and reseat it, but chances were that it would crack. If that happened, they could replace it with an aftermarket one for $600. But that could interfere with the cameras. The OEM one, which they guaranteed wouldn’t interfere with the cameras, was $2,500.


Naturally, the existing windshield cracked when they went to unseat it—because of course it did. I told them to slap the aftermarket one on and the whistling stopped. Unfortunately, the week after that, I got a big chip in the windshield, which I had to get filled.

The A8, getting its windshield filled in my driveway. A previous COAL, the 2000 528i, makes a cameo here.


And that brings us to the final issue, which is the transmission. The A8 did fine for several months, a year in fact. And then, the ZF 8-speed began sometimes hesitating on the 1-2 upshift when accelerating. On the 2-1 downshift, it would buck harshly into first. I perused the Audi forums and it was a common issue, which a lot of people solved by updating the TCM to the latest software version. I had the dealer do that and a flush, and it affected it not at all. It would only do it one in every six stops, but it was still annoying.

Me, in the A8. I believe I was at the gas station.


I still have the Audi, and have made the decision, as of this week, to have a second flush done. If that doesn’t solve it, it gets sold. At that point, it’s either the valve body or the transmission itself. Could I spend $3,000 and replace the transmission with a used unit? Sure. But I’m not going to. It seems to me like a good opportunity to dump it for something else. I’m sure I could still get at least $10K for it, which is not much less than I paid. I do really like the A8 and the way it drives and would keep it if not for that. I’m honestly not too upset, because I got to put 20,000 miles on it; as you’ve read here, I’ve done a lot worse in the past.

One last question: Why are VW Group steering locks so loud?