The Aston Martin DB9 Automatic Transmission

I’ve been curious to learn more about the Automatic Transmission fitted to the DB9’s.   I’m talking about the 6-speed Touchtronic II paddle shift unit that was in the majority of DB9’s from 2004 until 2014 when they changed to the Touchtronic III 8 -speed.  The DB9 had an option for a 6-speed manual transmission (stick shift) but those are rarer and I don’t have one.

What got me wondering were a few common sense questions:

  • How do you tell if the transmission fluid is topped up?
  • When does the transmission fluid need to be changed?
  • Is there a transmission fluid filter that needs to be changed?

Surprisingly, there were no simple answers.  Here’s what I learned.

[Spoiler Alert!  If you own a 2004-2011 DB9, you are overdue for a Transmission Fluid Change]

Don’t confuse the Automatic Transmission Fluid with the Rear Transaxle Fluid

For better weight distribution DB9s have their transmissions located in the back of the car just ahead of the rear wheels.  To save space, the Automatic Transmission is  bolted directly to the front of the Rear Transaxle (differential).   See the diagram below.  The two components are separate in their function, and in their service needs.  The rear transaxle needs its fluids changed every 2 years (read my article on how to here)  as part of the 2 year annual service regime.  It takes completely different fluid.  This should not be confused with changing the automatic transmission fluid.

Owners Manual and the Service Schedule

I started my research where we all should – the owners manual to review the service schedule.  There is only one item to inspect for leaks and top up the fluid if needed.  No interval for changing fluid or filter.

Workshop Manual

Next I checked out the official Aston Martin Workshop Manual Section 7.01 on the Automatic Transmission.    It reveals that the transmission is a ZF 6HP26 transmission.  ZF makes transmissions for many manufacturers, and the transmission itself is NOT bespoke to Aston Martin.  It’s used in BMWs and other brands.  Aston did design & test the cast aluminum housing for the transmission since its an integral part of the rear suspension and transaxle.  To recap – the case is bespoke to Aston Martin but the transmission guts are ZF.

The manual says the transmission is

Filled for Life

Implying that there is no service required _ever_ for this transmission.  I find this unrealistic.  “Life” of what?   Me?  First owner?  Or the transmission’s life until it self destructs from deteriorated fluids.  The latter is my concern.  It makes the skeptic in me wonder what best serves the companies?  It needs to last beyond the warranty period before dying, then we can sell something very expensive to replace it.

The workshop manual does list some procedures for checking and topping up the fluid level should a leak have occurred.   For example if you have a leak in or have to change your transmission fluid cooling lines.   It lists the recommended transmission fluid as “Shell ATF” but honestly this isn’t nearly detailed enough – and I will cover the correct fluid further along in this article.  Its not the typical automatic transmission fluid you’d pick up in your local Shell service station and use in your mini-van.  Fluid must meet Shell standard M1375.4.

The manual also lists the fluid capacities as:

  • 10 liters
    • I think this is for a completely dry transmission, and is more than what an oil change will require.  You’ll see below that the official ZF service kit include less replacement oil.
  • 1.6 liters for the transmission fluid cooling system

Wikipedia

Knowing the model of the transmission, I went to Google and searched ZF 6HP26 and found there is a complete Wikipedia page on all sorts of details about this transmission (you can find it here).   Wow – who writes all that stuff?  I am glad they did.   On the page you can actually see a list of all the variations of the transmission, and see a confirmation that it was in fact used by Aston Martin.

When introduced the ZF 6HP26 was the first 6-speed automatic transmission.  Aston was on the forefront of technology when the DB9 came out.  The 6 in the name is the number of gears.  The ’26’ at the end refers to the torque its designed to handle.  The 6HP26 was the original model and is rated for up to 600 Nm (442 lb-ft), and this worked well with the DB9’s V12 engine that produces 570 Nm (420 lb-ft) of torque.

Note:  If you plan on adding performance tuning to your engine to raise the power, take note of how close the stock engine is to the max torque rating for the transmission.  22 ft-lbs more (5%) of torque will max it out.

Although it went out of production in 2014, ZF made over 7 million of these transmissions worldwide between 2001 and 2014!  Wow.  What should be good news about this is that we won’t have to get service parts ONLY from our local Aston Martin dealer (where they would certainly be more expensive).  It also means the aftermarket parts companies have come along and made OEM equivalent parts, but cheaper of course.  In fact you can even find the service parts on Amazon.   I’ll cover the parts more extensively in the future article on changing the fluid.

ZF’s Website

A little more Googling on ZF 6HP26 turned up the official ZF website, and their actual Transmission Oil Change Service Procedure.  The holy grail of how toYou can find a copy of it here.  Comparing it to the Aston Martin Workshop Manual section on checking and filling the transmission is a pretty close match in process.  I’ll be relying on this procedure when I do mine.

The ZF guide has a few more great things on it:

  • Specifies the exact fluid to use – ZF Lifeguard 6.
    • This stuff isn’t cheap, but can be found from multiple sources online for about $25 USD per liter.  You can see where most of the cost in the Service Kit come from since we need 7 liters or more.
    • The official standard the fluid meets Shell standard M1375.4.
    • The forums like Pistonheads and 6SpeedOnline have lots of threads and rambling discussions about what fluids are OK to use and alternatives.  I’m less keen to save $20 on something I will do precisely once every 8 years or so.  In the future article I will list some fluids I find that meet the grade, but I expect you’ll see me using the official ZF fluid.
  • Specifies a Service Procedure for Aston Martins (Table A)
  • Specifies the Torques and Pattern for reinstalling the plastic oil pan.
  • Specifies an official ZF Service Kit that includes that they think is necessary to change/replace when changing the Transmission fluid.  This is GREAT to find, the definitive recommendation on what you should be changing in this process.  ZF part number 8700 252.  Googling you can find this online from a few suppliers, mostly in the UK.  It includes:
    • Replacement Oil Pan.   This seems extreme only until you learn that the transmission oil filter is built into the drain pan, and you have to change the pan to change the filter.
      • Fun Fact – the oil pan is made of PLASTIC.  Yes, the original is too.  ZF designed it this way.
    • The replacement oil pan has a gasket/seal that comes with it
    • Replacement bolts (21)
    • Replacement Fill Plug
    • Seven (7) liters of ZF Lifeguard 6 fluid

What about the Transmission Fluid Cooler?

The DB9 is fitted with a transmission fluid cooler.  There is a small extra radiator nestled just behind the lower front bumper grill, and its connected back to the transmission with two really long pipes that are a combination of hard piping and flex hoses.  They connect to the transmission just above the fill hole on the right side.

If we drop the drain pan and drain the oil from the transmission, it doesn’t drain the approximate 1.6 liters of fluid in the radiator and lines.  Leaving this in wouldn’t be the end of the world, you’d be diluting the 1.6 liters of old fluid with the 7 liters of new, so you’d have changed 82% of the oil, leaving 18% old.   None of the procedures talk about this, but I expect I’ll find a way to drain this oil when I do the project.   Hmmm, I’ve got to remember to order 2 extra liters of fluid for this.

How often?   Time for a decision.

I’ve managed to find answers to how to check the levels, how to change the fluid and what parts to use, but I still don’t have an answer for how often.   I don’t agree with the ‘filled for life’ scenario.   Reviewing the Internet Forums reveals lots of discussions about a filled for life service interval, but nothing definitive.  I even chatted up Aston Martin Technician Scott Garvin to ask him, and his opinion was to leave it alone unless you see it leaking.

I can’t get past the fact that transmission fluid is just a specialty form of oil, and oil breaks down over time.   Particulates of wear build up in the fluid, ones smaller than the filter is designed for.  The transmission is not sealed from the atmosphere either, there are breather tubes that allow it to maintain an equal air pressure inside the tranny.  This will allow some moisture to enter and interact with the oil.   I think it will need periodically changed to stay in good condition.

The ZF Service Guide actually answers this question right on page one:

ZF Automatic transmissions are filled with specially developed semi-synthetic oils.  At very high operating temperatures, the oil ages faster than under normal conditions.  Examples:

  • Many trips at high speeds [this might apply to an Aston!]
  • Many trips while towing a trailer [Ha!  Not so much with an Aston]
  • Sporty driving [definitively describes an Aston]

Depending on the driving style, ZF recommends a transmission oil change every 80,000 to 120,000 km or after eight years at the latest.

There you have it.  Eight years at the latest.  Not filled for life.  Yikes.  This means every DB9 from 2004 to 2011 is overdue for a change right now.

How Much to do a fluid change?

Since the ZF service kit is available online for about $370 USD, I would expect that would be the cost of parts if you are following the official ZF way and doing the work yourself.

If you take your car to an Aston Martin dealership I could see the cost being double on the parts, plus the labor costs and you’ll be over $1,000.   I’ll track down an official estimate when I get to doing the project.

What would a replacement Transmission cost?

I was curious to track down how much a replacement transmission would cost.  If we followed the ‘filled for life’ mantra and let transmission eats itself, just how ridiculous would it be to replace?

Just getting a used transmission from a dismantler is about $2,700 USD (plus tax, shipping and installation).

A refurbish transmission, torque convertor, fluids and installation looks like about $6,200 USD from a specialist.

New from Aston Martin?  How about $8,770 just for the transmission and torque convertor (plus tax and shipping and installation)!   Looking at over $10K USD to do it at the dealership.

I think I’m going to try and extend the life of my transmission and change the oil for a few hundred bucks.

What’s Next?

I plan on changing my Automatic Transmission fluid in the year ahead.  I will do an article on where to get the correct parts at the best prices.  I will do a series of articles that will probably include how to move the right exhaust pipe out of the way, drain the fluids, install the parts, refill the fluid, and how to check the fluid levels.   When I drain the oil and inspect the pan for sludge we’ll be able to see the condition.  Stay tuned!

Please leave me comments down below with your opinions on my thought process, any personal experiences you’ve had with this, and any questions you have.

 

14 thoughts on “The Aston Martin DB9 Automatic Transmission

  1. Paul Tester

    Another great article. I have higher mileage aston (60k) and have been asking myself exactly the same questions.
    The transaxle started life as a sealed unit, but as you say, the oil is now to be changed regularly. I started to experience grinding and gabbing when slowly pulling out from a junction while turnung, changing the diff oil and filter cured it completely.
    I look forward to your future article when you eventually change yours.

    Like

  2. Adi Horrell

    Great article as normal Steve. My AM is coming up to 13 years old but with only 22,000 miles. In my wildest dreams I would like to think that the dealership did all this work prior to me buying 3 years ago, but of course, that is a wild dream.
    Can’t wait to see your video and how that fluid looks when you post it.
    Thanks
    Adi

    Like

  3. Russell Taylor

    Hi Steve,
    This whole sealed for life thing doesn’t sit well with me either. I did some research a few months ago and basically came up with the same conclusion as you. If it’s over 8 years , it’s time to replace. I haven’t done the work yet but I understand there is a few small items to replace while your in there. There are some seals that are located behind the valve body that are not too hard to get to and replace. Apparently over time they flatten and allow fluid to bypass them causing shift issues. My understanding is that they are not expensive and relatively easy to get to once you are in there. This video link is not an Aston but it is a ZF6 and the guy does a pretty good job of showing what we are in for. Does your Aston tech have any additional input on these seals needing replacement. https://youtu.be/7S-TXP5o7nE

    Like

    1. Hi Russell. The first Aston tech didn’t say much about the seals. I’m checking with another. From the research so far it would be wise to do the Mechatronic Bridge Seal, plus those 4 port seals, the electronics sleeve, and the pan inclusive of the gasket. Toss in $300 of ZF Lifeguard 6 oil and bobs your uncle. I’m rounding up parts and fluids, and background on the selection of each. I am going to try and get ahold of an official ZF service kit as well for comparison. Has me wondering if I will feel the difference at all afterwards. About all I can feel that might be ‘off’ is my downshift from 5th to 4th is a bit abrupt, enough that I can feel it where I can’t in the other shifts. Hope it goes away afterwards, would be a sign that the fluids were ‘off’. Stay tuned!

      Like

  4. Looking at an 2002 12cyl DB7 Vantage Auto with 42,000 miles on the clock. Seems you & I might have the same engine & gearbox ? Read all your blog about running costs & I agree – Aston Martin ownership ain’t for the faint-hearted !!
    I had a ’77 V8 auto – never broke down on me,used it everyday,until pot 5 & 6 blew… going rate for a rebuild £18-20,000 then – used another car,that’s when DB 7 caught my eye. Luckily it had Plugs & Coils renewed earlier this year,& any rust to the undercarriage sand-papered off & painted with correct protection.
    FYI – I happen to live One & Three-Quarters of an Inch away ( from HWM…) on the Map !! NO,I’m NOT buying from them,(their car prices are too high)
    I was quoted / told by several people that MPG was 8 MPG-ish Urban, & maybe 23 MPG on a long run ?
    Don’t hesitate to make contact if you need someone to speed them up anytime,glad to help another Aston man !

    Like

    1. Hi David. Thanks for sharing. I think the 2002 Vanquish used an earlier model ZF transmission, the 5HP30 perhaps. I am no DB7 expert to be sure. Neat that you live near HWM. They’ve been flexible on price with me, and other Aston1936 readers. In a pinch try name dropping if you need something they have and you don’t want to drive 2 inches. I’d think 10-20% off might be feasible. Thanks for reaching out!

      Like

  5. craig elam

    its not a bad job to do really, you dont have to remove the exhaust as per manual, just shorten you 8mm allen key to undo the plug, removing the sump is easy until you realise that theres one bolt (as always) that you cant get out without removing the pipes to the themostat, the pipes are secured with tube nuts just like giant brake pipes, top tip clean and then lubricate the tube nuts so as you undo them they dont bind on the pipes, theres a couple of o rings where the pipes go onto the box , i didnt have any so re used originals , they dont leak so all good, i bought a 2ltr syringe from eurocarparts which made refill easy, I too believe filled for life to be a nonsense!!

    Like

    1. Thanks for all the tips Craig. I was wondering about the oil cooler lines and also if the right exhaust pipe needs to really come out. Did you change the ~1.6l in the oil cooler lines too?

      Like

  6. Paul

    Hi Steve,
    Great article as usual.
    My Rapide (4door DB9) has 55k on it and I’m ready to do the transmission flush.
    I can’t wait to see your procedure.
    Keep up the good work!

    Like

  7. Craig Elam

    Hello steve
    I didnt find a way to drain cooler lines, but as you said earlier its not a big problem, im in uk and the oe ZF sump/ filter was about £60.00 from euro car parts , i managed to change nearly 7 litres,

    Like

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