The Due south tronic Gearbox Bible

This post covers everything you demand to know virtually the Audi S tronic dual clutch gearbox fitted to the B8 and B8.5 S5, from how it works, to how much ability (torque) information technology can handle, tuning options, common bug and faults and when it needs servicing.

Audi S tronic 7 speed gearbox transmission cutaway engineering diagram This post may contain affiliate links. Please read my disclosure for more info.

Contents

I'd recommend reading through the whole article, simply if you're in a hurry y'all tin skip to a specific section of this commodity using the links below.

Audi S tronic vs DSG vs multitronic vs Tiptronic?
How Does the Audi S tronic Gearbox Work?
South tronic Gearbox Variants
Due south tronic Service Schedule
Modifying a Car with an Due south tronic Gearbox
S tronic Remap (TCU Upgrade)
Audi 7 Speed S tronic Issues and Reliability
Symptoms and Fault Codes
Audi Southward tronic Mechatronic Unit Repair Options and Costs
Audi S tronic Dual Clutch Repair Options and Costs

Why Write About the S tronic Gearbox?

The idea hadn't even crossed my mind to write a post about the Audi Southward tronic gearbox, that was until I discovered how piddling I knew about information technology. Shameful really having owned my S5 well over a yr now...

Whilst researching the S tronic service / maintenance schedule, I stumbled across the cutaway technology cartoon of the S tronic transmission beneath and was fascinated past just how complex it appeared, and naturally wanted to acquire more.

Many hours of reading later I started composing this mail service. I know it's a bit of a diversion from my usual content but stick with it because I hope you'll detect it as interesting to read as I found writing information technology (you're bound to if you're an engineering nerd similar me).

Audi Due south tronic vs DSG vs multitronic vs Tiptronic?

The kickoff thing to boom down is, what does Due south tronic mean? The answer is... non a lot, it'southward just Audi's name for their latest DSG (Straight-Shift Gearbox) offering. S tronic and DSG can be used interchangeably if y'all then wish, notwithstanding, Southward tronic is definitely not the same as multitronic or Tiptronic.

In short, S tronic is a dual clutch DSG and has a number of variants, both longitudinal (as fitted to the S5) and transverse, and 6 or vii speed.

multitronic is a continuously variable transmission (CVT), it works by running a tension chain betwixt two pairs of variable conical pulleys. Moving the pulleys further apart or closer together changes the gear ratio. For a full description visit the Multitronic Audi Engineering Portal page.

Tiptronic is a more traditional automatic gearbox featuring a torque converter, every bit appose to the dual clutch of the Due south tronic manual. For a full description visit the Tiptronic Audi Engineering science Portal page.

How Does the Audi S tronic Gearbox Piece of work?

Elaborating on my brief description earlier in the post, here's Audi's total description:

Audi S tronic gearbox operating principle diagram
"The S tronic [gearbox] comprises 2 subunits and integrates two multi-plate clutches that control the various gears. The large K1 clutch located on the outside directs the torque via a solid shaft to the gear wheels for the odd-numbered gears 1, 3, 5 and 7. A hollow shaft rotates around the solid shaft. It is continued to the smaller K2 clutch, which is integrated into the within of its larger sibling, and which controls the gear wheels for the even-numbered gears 2, 4 and six, besides every bit the reverse gear."

"Both transmission structures are continuously active, simply but 1 is continued to the engine at whatsoever one fourth dimension. For instance, when the driver accelerates in third gear, the fourth gear is already engaged in the second transmission structure. The shifting process takes place equally the clutch changes – K1 opens and K2 closes."

This means that the Due south tronic gearbox tin can shift gears in under 0.ii seconds offering almost seamless power commitment, pretty damn impressive!

I'm a large fan of the Engineering Explained YouTube aqueduct, and then any excuse to promote Jason'due south videos and I'm on it. In this video he explains how a VW Passat transverse DSG works.

For an even more than in-depth look at the 0B5 gearbox, Google "Audi Self-Study Programme 429" or "SSP 429" and skip to page 22.

S tronic Gearbox Variants

There are a number of variants of the S tronic transmission, the original existence the transaxle DQ250 (part number prefix: 02E).

In 2008 Audi developed the longitudinal S tronic gearbox constitute in the B8 and B8.5 S4 / S5, code named DL501 (function number prefix: 0B5). It weighs 142kg including the dual mass flywheel and oil. In that location are multiple generations of the DL501, Gen 1, Gen 1.5 and Gen two.

Due south tronic Service Schedule

If maintained, the S tronic gearbox is usually pretty reliable. Quoting Audi UK, "To ensure the continuous smooth running of your [S tronic] transmission it is essential that the oil is changed no later than every 38,000 miles [61,155 km]."

Audi service workshop area
In the Great britain, Audi offers an S tronic manual oil and filter change for a stock-still cost of £225 (2020 toll), non outrageous which suggests it'south non too difficult or fourth dimension consuming should you wish to DIY.

Update: Oct 2019

My S5 Sportback is now well overdue the Southward tronic transmission oil service, I know, I know, I have brought great shame upon my family...


Anyway, I've purposely been belongings off, partly because life has gotten in the manner only more worryingly, because I'm getting the dreaded "Gearbox malfunction: you can keep driving" warning.

I've been doing even more Googling, forum reading and youtubing to nail down exactly what I need to replace. I will of course be doing a full update of this commodity with what I've learnt.

Parts Required

If y'all purely wish to replace exactly what Audi would, during their £225 service, you'd need the following parts:

  • North 013 827 v - Sump drain plug washer x1
  • 0B5 325 330 A - Exchangeable external ATF filter x1
  • WHT 005 499 A - O-ring for external ATF filter x1
  • WHT 003 487 - New replacement sump bleed plug x1
  • Yard 052 529 A2 - ATF gearbox oil 7L

You should see this option as the bare minimum. If you're going to the trouble of doing the service yourself, you might as well become all in and supercede the internal filter besides, not only does this allow you to bleed more of the old oil, it allows y'all to check the magnets in the sump pan for whatever debris. If you desire to supplant the internal filter, you'll demand the post-obit parts in add-on to those to a higher place:

  • N 911 511 01 - Cross Fellow member Bolts x6
  • Northward 910 968 01 - Oil pan bolts x15
  • 0B5 321 371 E - Oil pan gasket x1
  • 0B5 325 429 Eastward - Internal filter / strainer with O-rings x1

I'll be going one stage further, and carrying out a DIY mechatronic unit repair, then for that I've ordered the post-obit:

  • WHT 005 379 - Oil seal between external filter housing and gearbox x1
  • 0B5 321 473 - ATF pipes inc seals between external filter housing & gearbox x2
  • N 906 660 03 - O-ring for metal pipes going into external filter housing x2
  • N 104 057 02 - Mechatronic unit mounting bolts x6
  • 0B5 315 105 TC - Mechatronic clutch pressure pipes x1
  • 0B5 315 105 TA - Mechatronic internal ATF pipes x1
  • 0B5 398 009 F - Mechatronic PCB repair kit x1

The RRP of all these parts is £643.98, I was able to go them for £592 delivered. All will exist explained if information technology works out ok, I want to brand certain everything comes adept before recommending information technology to you guys.

Tools Required

In terms of any special tools required, you'll need the following:

  • VCDS or OBDEleven (or like) to read the live transmission oil temperature
  • Low Range Torque Wrench with 3Nm setting - For Mechatronic Repair Only
    • I'll be using a Norbar 15008 Professional

I'll exist writing my own DIY guide on how to service your 7 Speed Due south Tronic DSG manual and DIY mechatronic unit repair simply for now, cheque out this first-class video below from Deutsche Auto Parts.

Modifying a Auto With an S tronic Gearbox

The longitudinal 7 speed S tronic gearbox can handle torque figures of upwards to 550Nm at 9,000rpm according to the Audi Self-Study Program 429 (SSP 429).

As standard the 3.0 TFSI supercharged V6 in the S5 puts out 440Nm of torque, well within the South tronic's capabilities.

Cheers to the huge tuning potential of the 3.0 TFSI yous tin cease upward getting much closer to that 550Nm limit quite easily.

TMC Motorsport chip tuning box

Yous should exist safe with but Stage I modifications though, in my postal service on choosing the all-time Audi S5 V6 chip tuning box, all of the tuning boxes claimed to add together in the region of 50-75Nm of torque, and so topping out at 515Nm. Closer to the 550Nm, simply nevertheless safety.

APR Stage 1 ECU Upgrade vs Stock graph Audi 3.0 TFSI S4 S5
If you become one farther and opt for the April Stage II ECU and supercharger pulley kit on 98 RON you'll be pushing 535Nm, on 108 RON race fuel yous'll exist on the limit at 554Nm.

APR Stage 2 II ECU Upgrade and APR Pulley vs Stock graph Audi 3.0 TFSI S4 S5
Although Audi cite 550Nm as the maximum torque, I did notice one post on a5oc saying MTM had confirmed the S tronic gearbox can handle 600Nm+, and a company from the Netherlands called TVS Engineering quoting as much as 1000Nm (with their software).

I got in touch with Audi's technical team who confirmed:

"The torque chapters of this [the Southward tronic] transmission is upward to 550 Nm at 9000 rpm."

S tronic Remap (TCU Upgrade)

There are a number of companies offering a remap, or transmission control unit (TCU) upgrade, for the Due south tronic manual. I've listed a few of the more than popular ones below.

  • Revo S tronic Stage 1 - £358.eighty
  • TMC Motorsport AutoFlash ii - £478.lxxx
  • Apr DL501 S tronic TCU Upgrade - £720.00
  • *All prices correct every bit of 18/08/2018 and include VAT.

Every bit I found out when researching chip tuning boxes, the price can vary wildly. Each visitor has their own USP, but nigh offer the post-obit benefits from their remaps.

  • Reduced gear change time (TMC claim a 28% comeback)
  • Launch Command enabled
  • Increased max Launch Command RPM (Apr offering up to half dozen,000 RPM)
  • Torque limit increased
  • Total manual mode (no automatic alter at max or min RPM)
  • Automated shift RPMs modified

The graph below from APR shows acceleration vs vehicle speed, demonstrating the APR TCU maintaining a college G throughout the gear range.

APR DL501 vs Stock TCU S tronic remap graph 3.0 TFSI S4 S5

Audi seven Speed S tronic Issues and Reliability

Every bit technically vivid as the S tronic gearbox is, it does have it's issues, very costly ones at that. Probably the almost high profile case of Due south tronic gearbox problems is that of Peak Gear's Chris Harris on his S4 estate, back in 2014.

Chris Harris S4
You can read the full commodity on PistonHeads, but basically it ended up costing him £4,129 inc VAT for a total gearbox replacement (an extremely good cost, because a new gearbox would cost the 'general public' £12k+).

Chris Harris gearbox S4 replacement
From what I've read, the 2 main culprits for 7 speed S tronic problems (or failure) are the dual clutch and the Mechatronics unit.

Symptoms and Error Codes

Symptoms of a faulty or failed S tronic Mechatronic unit of measurement tin be poor gear selection or no gear option at all. If there is harm or fault with the dual clutch, you might experience jolting gear changes, loss of torque moving off in reverse gear and loss of power. The Mechatronics unit appears to be the most mutual source of problems for the Southward tronic manual. Quoting SSP 429: "The mechatronic system controls, regulates and performs the following functions:

  • Adaptation of oil pressure in the hydraulic system to requirements
  • Dual clutch regulation
  • Clutch cooling regulation
  • Shift point selection
  • Gearbox control and regulation
  • Communication with other control units
  • Limp-dwelling house programs
  • Self-diagnostics"

Note: Inconsistent or harsh gear changes can exist caused by a MAP sensor failure, check out my complete guide to replacing your MAP sensor for more info!

According to the Audi Technical Service Bulletin SB-10054213-2278 if you go the following message announced in the data display:

"Gearbox malfunction: you can go along driving"

Audi Gearbox malfunction: you can continue driving warning message and light
The following fault codes may have been recorded and could point to a faulty Mechatronic unit.

  • DTC P17D8 (Torque limitation considering of clutch temperature) with symptom code 8040
  • DTC P0726 (RPM betoken of engine control unit, implausible betoken) with symptom code 7980
  • DTC P174B (Valve 4 in the sub-gearbox one, electric error) with symptom code 8027
  • DTC P174F (Valve iv in the sub-gearbox 2, electric fault) with symptom code 8028
  • DTC P179C (Principal pressure level valve, electric fault) with symptom code 8029
  • DTC P179D (Coolant oil valve electrical fault) with symptom code 8030
  • DTC P174C (Partial transmission one valve 2 Electrical error ) with symptom code 8026
  • DTC P174A (Valve 3 in the sub-gearbox i, electrical error) with symptom lawmaking 8939
  • DTC P174E (Valve iii in the sub-gearbox 2, electric fault) with symptom lawmaking 8940
  • DTC P1740 (Clutch temperature monitoring) with symptom lawmaking 8031

Too as the in a higher place error message, there are two others you may experience:

"Gearbox fault: You can proceed driving to a limited extent just"

Audi Gearbox fault: You can continue driving to a limited extent only warning message and light
If the above message shows, protective functions are activated to minimise or prevent harm occurring, but result in a loss of performance. Only the gears on the hollow shaft can exist engaged (fifty-fifty-numbered gears 2, iv, six and R).

"Gearbox mistake: You can proceed driving to a limited extent only No reverse gear"

Audi Gearbox fault: You can continue driving to a limited extent only No reverse gear warning message and light
If the higher up bulletin shows, protective functions are activated to minimise or prevent damage occurring, just upshot in a loss of performance and with no ability to select Opposite gear. Merely the gears on the solid shaft can exist engaged (odd-numbered gears one, 3, five and 7).

Audi South tronic Mechatronic Unit Repair Options and Costs

The cheapest way to repair your Mechatronic unit is to do it yourself following my DIY Mechatronic unit of measurement repair guide.

However, if y'all'd rather non mess around with swapping circuit boards, but don't mind removing / refitting the Mechatronic unit and doing the Southward tronic service, you have these two options:

  • Ecutesting.com Repair Service - £400+VAT +£15 Aircraft
  • Gearbox Nottingham Replacement Mechatronic Unit - £850-£1300+VAT

*All prices correct as of 26/11/2020. I've not used whatsoever of the in a higher place companies, nor am I sponsored or paid to endorse them. Delight only function with your hard earned coin when y'all are happy the company will provide the service you wait.

Be mindful the prices above don't include all the parts required to do the South tronic service nor the replacement parts you'll need every bit a event of removing the Mechatronic unit (seals, ATF fluid, filters etc).

Y'all'll probable need to add at least £350-£400 on top of those prices.

If you lot want the whole task doing for you, yous're looking at £2300+ (based on a effigy taken from AC'due south quote on rmsmotoring)

Audi S tronic Dual Clutch Repair Options and Costs

Audi Britain offers a fixed price quattro clutch service, which for my S5 is quoted as £1799 (ouch). Unfortunately Audi doesn't give any details equally to what work is carried out for that sizeable sum of cash.

I did contact Audi for more than info, but they replied with the post-obit:

"Your local Audi Centre will exist happy to confirm what work volition be undertaken at the fixed price clutch series"

If you work for Audi, or have had this repair done to your car I'd beloved to hear your experiences, allow me know in the comments below!

Determination

That concludes the article for now, as I learn more I'll continue information technology continually updated. I really hope you enjoyed this post despite being away from the norm, if y'all did and would like to run into more articles like this, let me know in the comments below. Can y'all add together anything to make the guide even more complete? Take you been stung by having to repair or replace your Southward tronic gearbox and are there whatsoever pointers or lessons learned y'all can share in the comments? Exist certain to Like, Subscribe and Follow me on whatsoever or all of the usual social media platforms at the post-obit links: Facebook, Instagram and YouTube, search andybuck123.

Stay tuned for plenty more than content to come!