Technical Session 2008


November 26, 2008

The 2008 edition of the Volvo Club of BC winter Technical Session was held at Volvo of North Vancouver. Tony Do discussed the pros and cons of transmissions fitted to various models.

We expect to have the technical writeup posted here in the near future. In the meanwhile, members with a login can view a copy of the handout provided to us.


Volvo of North Vancouver hosted our technical session for the 4th consecutive year. Ian Peterkin, taught the sessions for the first 3 years and last year he was assisted by Volvo Master Technician Tony Do. In 2008 Ian was promoted to Parts and Service Manager at Volvo of North Vancouver and now is up to his neck in paperwork, rather than mechanical work, so Tony volunteered to give the session. Tony graduated from the BCIT Automotive Service Technician Program as a coop student in 2001. At that time Volvo of North Vancouver was looking for a technician and the BCIT Coop Department arranged for Tony to be interviewed by Mike Thompson and Tony was hired.

Our group of people at the tech eission
2009 Tech Session - Volvo of North Vancouver. Tony Do, far left.

Tony is now a master technician. I asked him how you move through the Volvo technician ranks and he explained. When you start with the company you are on a 3 month trial period or probation. In Tony’s case the next step was a 2 year apprenticeship he earned the “Certified Technician” designation recognized by the North American automotive industry. After that the he was eligible to enter the Volvo Technician program. The first step is Volvo Quality technician and that takes 1 year, and 4 instructor lead training courses and 4 open book exams. The next step is a Volvo Certified Technician which takes another year, 4 more courses and 4 exams. After that comes the Volvo Master Technician qualification for which you have to have worked at Volvo for at least 3 years and take 3 courses and pass another 4 tests. The final level is Volvo Expert Technician requiring a minimum of 5 years with Volvo, 4 instructor lead courses, 4 on-line courses and a thesis of a subject chosen by the company. Tony will reach the Expert level later this year. No wonder he knows what he is talking about.
All these certifications are Volvo-wide and are transferable between any Volvo dealership. Depending on the size of the dealership and the number of technicians working in Service, Volvo stipulates the mix of technician qualifications. For instance in a medium sized shop of perhaps 8 technicians, there must be at least 1 Master, 2 Certified and 2 Quality technicians on strength.

Volvo obviously takes the quality of their service very seriously and trains their service technicians very well. To promote continued excellence, Technicians with Master or Expert certification can enter regional competitions. For instance there were 72 technicians competing in the BC/Alberta regional competition and the top 4 techs advanced to the North American finals. Tony was in the top 4 this year and went to the Nationals in Phoenix. The winners from the Nationals go to Sweden to compete with Techs from all over the world.

Back to our tech session. Tony suggested the subject of Automatic Transmissions for this year’s event and he prepared an excellent handout that summarized the History of the various automatic transmissions used in Volvos from the 240 series to date, and gave some basic mechanical principles of automatic transmissions.

There were 20 of us in the shop and Tony invited us to ask him questions, but warned that he is not familiar with some of the older transmissions. When I asked how old is old, he smiled and said he would not talk about transmissions that are older than he is. Fair enough.

Tony proved to be excellent teacher. He fielded every question he was asked with accurate and candid answers. We all came away with an appreciation of the pros and cons of the various transmissions as well as some valuable preventive maintenance and repair advice.

To learn what we learned see the article in the Technical Tips section of this newsletter.


Presented by Tony Do of Volvo of North Vancouver
Gregg Morris (Note this article has been prepared using Tony’s handout and my notes from the tech session. If you notice any errors they are due to my interpretation not Tony’s presentation.)

1975 – 1995 Volvo 240, 260, 740, 760, 940

Depending on what model and year it may be equipped with a BW55, AW55, AW70 or AW71. BW was made by Borg-Warner and AW by Aisin-Warner. The BW55 and AW55 are 3 speed transmissions and the AW70&71 are 3speed and overdrive. A common problem with the AW70 and 71 transmissions is that the tail-shaft bushing wears and/or the tail-shaft seal leaks. It is recommended that both be replaced in the event that either the bushing or seal fail. A minor vibration may be felt when the rear of the vehicle is weighed down. The vibration is due to the 2 piece drive shaft straightening out and pushing against the center support bearing mount. Fixes include shimming the center support bearing mount, balancing the drive shaft and replacing any worn or seized U-joints.

1993-1997 Volvo 850 and 1998 S70, V70, C70

These are equipped with the AW50-42 which is electronically controlled. They came with a Sport/Economy/Winter switch. Sport mode would delay the shift point to utilize the high end power of the engine and Economy mode would shorten the shift point to have the engine run at lower RPM to save fuel. Winter mode starts the transmission in 3rd gear to reduce torque to prevent the wheels from spinning in snow conditions.

Early 850s had problems with their AW50-42 transmissions. Remember this was Volvos first foray into front wheel drive. In 1995 they made a lot of internal improvements which reduced failures. A common problem was failure of the gear position sensor which causes the transmission trouble light to flash and there will be a trouble code. The cause was a combination of water intrusion and heat and the fix is replacement of the sensor.

A problem specific to the 1997 850 Turbo AWD wagon, is a difference of 2 mm or more of tread wear between the front and rear tires can overheat the viscous coupling leading to noise or loss of rear wheel drive.

1991-1998 Volvo 960/S90/V90

These have AW30-43 (1991) or the AW30-40 (1992 -1998) electronically controlled transmissions. Common problem was the Park-Neutral-Position (PNP switch failing and causing the transmission to run in limp mode or even prevent the engine from starting if it does not recognize that it is in park. The transmission trouble light will flash and there will be a code in the fault tracing system. The solution is to replace the switch.

2001-2009 All Volvo Models

These are all equipped with the AW55-50, electronically controlled, adaptable and programmable transmission. The 2001 to 2005 transmissions are 5-speeds. The AW40-50 version is a 6-speed installed in most models from 2006.

The only exception is the first generation S80 and the 2003 XC90 T6 which used the General Motors 4T65. The GM transmission is a bit weak and although it wasn’t too bad in the S80 it was much more of a problem in the 2003 XC90 T6. A common, and terminal fault, was losing all forward gears. Metal shavings and debris can be found in the in the oil pan and in that case the transmission must be replaced along with the cooler lines and the radiator.

Although all the models used the AW55-50 transmission there are detail structural differences between the various Volvo models, but the function and faults are similar. These transmissions were continuously developed through the years so there are detail changes and improvements from year to year. They are generally great transmissions but they are being asked to handle a lot more power than Volvo transmissions used to and consequently have more wear issues than transmissions in the old 200/700/900 series cars.
The AW55-50s are electronic, adaptable and programmable. The adaptable part means the transmission modifies how it operates depending on how the driver drives. The programmable part means the computer that controls the transmission can be reprogrammed to change the operation of the transmission. This is very helpful.

Volvo has developed software downloads that can adjust for wear in the transmission. For instance delaying a solenoid by one millisecond can improve shift quality. Between 100,000 and 160,000 km most transmissions will develop some driveability symptoms and.
about 75% of the time a software download will cure the problem. The 6 speed AW40-50 transmission fitted from 2006 have not displayed any problems and Tony has not had to do a software upgrade on any of them yet.

The results of the software download are impressive, but you have to be careful when doing a download. You must not disturb the car’s thought processes while its brain is being upgraded. For instance if an electronic module were activated by something as simple as opening a door during a download it can cause all electronic functions in the car to quit and even fry the central $1000 computer.

As a rule of thumb if problems are intermittent there is a good chance it is a software problem. If problem is continual it may be mechanical.
Here are some examples of transmission problems:

  • hesitation , slipping, clunks
  • A harsh 2-3 upshift and 4-3 downshift. On early transmissions this sometimes was a dislodged washer in the B4 servo cover.
  • Delay from Park to reverse or Park to drive. Valve body failure, replace with a new updated one for $1600.
  • Losing all gears. Probably terminal.
  • Flare is a slow shift where engine rpm rises before gear engages.
  • Missed shifts. For example the transmission shifts from 2 to 4 then immediately back to 3. This can be software or even the adaptability feature.

What happens if a transmission fails completely? Tony says Volvo does not authorize their technicians to do complete transmission rebuilds and they do not provide parts for this purpose. If a software download ($30 or $80) and fluid flush ($180) or a component replacement does not cure the transmission then your choices include:

  • having the dealership install a Volvo replacement transmission (which will be a factory rebuild $7000), or
  • having your transmission rebuilt at an aftermarket transmission shop ($3000+) or
  • Installation of a used transmission (this works, but the transmission must be the same year of manufacture or newer than the one you are replacing.) For example the XC 70 transmission has gone through 6 generations with minor modifications between 2001 and 2006 so the transmission from a 2004 may not work in a 2006. The Dealer Parts departments can help to identify the various generations.

AWD used viscous couping for 2001 and 2002 From 2003 it used the Haldex electronic AWD system can experience solenoid failures and computer failures. Haldex AWD system pressure temp sensor failure causes binding on turns like a 4x4.

Geartronic equipped cars (i.e. the ones you can sequentially shift): From 2001 to 2004 the shift was considered a bit slow, but from 2005 on it is very fast shifting.

Dipstick: While we were discussing the V70 transmissions Dave McAree asked where you find the dipstick, and Chris Ainscough helpfully suggested the driver’s seat. Tony came to Dave’s rescue and said the dipstick is very hard to find. Since 2001, not including S80, the dipstick is located down near the lower rad hose. It is hard to get to and when you do it is usually hot. From 2005 dip sticks have been deleted in favour of overflow plugs like we are familiar with in the side of M40, 41, 46 etc.

Preventive Maintenance

Have your garage keep track of you transmission function and get the available downloads.
Have regular transmission fluid flush and changes. Mountainous countryside like you find in BC is tough on transmissions and the fluid. Tony suggests transmission flushes at twice as often as recommended in the manuals.
All 1999 and newer transmissions, (except the GM transmission in the S80 and 2003 XC90 T6) uses synthetic transmission fluid. The Volvo fluid costs $30 per liter and it takes 12 litres ($360) to do a flush. Volvo of N. Van has a BG transmission flush machine that uses synthetic fluid and they do a complete flush for $180. It is a good fluid and obviously a good deal.

(Club member John Cripps (Mechanical Engineer) sends this comment on the cost of synthetic brake fluid. “Gregg, once my heart beat settled down after hearing the cost of Volvo's ATF at about $30 per liter for 1999 and later Volvo- Aisin Warner auto transmissions I did  a little digging on the internet.   Check IPD's website - the cost is about 7 to $8/US qt and the oil is made by Mobil for Volvo.  Is it a pure synthetic?  Likely not. The line between mineral oil and synthetic can be blurry with blends being available today.  In the absence of any mention of synthetics, I call it a mineral based oil. The bottom line is what fluid the transmission manufacturer (Aisin) specifies, not the car maker - these transmission are used in a variety of different cars.    Check Aisin's website.”) 

First Generation S40 and V40.: transmissions seem to be bullet proof and Tony has yet to see a problem with one.

Manual Transmissions: Tony said manual transmissions generally do not give problems except for clutches. Again the huge power can be a problem, particularly when the owner doesn’t know to use a clutch properly. He saw one R car owner fry his clutch in 20,000 km. Manual transmission fluid change interval is 150K or when the fluid starts getting dirty.

Differentials: Have proven to be bulletproof.