About three years ago I wrote a blog about the earlier Aisin Warner aw50/55 Auto gearbox used in the larger 5 cylinder petrol and diesel engines fitted from 1999 until 2005. It was very successful and many have asked for more information regarding the newer TF80 SC box fitted to cars from 2006 onwards. So here we go….
This gearbox is a bit more reliable than the former, but has several issues that can cause similar symptoms to the older box.
When TF 80’s go wrong they often become undriveable quite quickly and there are several things that can go wrong. If you start to experience harsh shifting, slipping in gear (or flaring) nine times out of ten, this is a valve body issue. They can be so bad that the gearbox feels totally beyond repair, although this is not usually the case.
Volvo and their insistence that the gearbox is sealed for life strikes again… For some unknown reason, possibly to appease leasing companies and reducing servicing costs, Volvo do not include an automatic fluid change on this gearbox (or the old one) claiming the gearbox is sealed for life unless the vehicle is used as a taxi or for heavy towing. The fluid used in these gearboxes is very high quality. However, when it gets very hot, it can break down over a period of time and become less effective. So, unless the fluid is changed at around 50,000 miles, it will cause issues in the auto gearbox.
The TF80 gearbox seems less prone to wear on the friction surfaces than the earlier box, maybe because it has an extra gear. As a result treatments such as Lucas Oils (which work well on auto gearboxes with worn friction surfaces) tend not be be as effective.
Even so, the usual practises still apply. If you start to experience issues it’s best to check the basics first.
Change the gearbox oil, use the correct JWS3309 approved oil, such as Castrol Transmax or the Q8 equivalent which we now use. We offer an EDT flush now, which will remove 97% of the oil and also put a cleaning agent through the box.
Check your software is up to date, there have been at least two updates from Volvo since this gearbox was first introduced.
Check there are no other issues in the system such as worn ABS rings or loose driveshaft bolts. The diesel engines have a habit of throwing gearbox faults when the injector wiring is faulty, it normally means poor performance too, but not always. Any issue, even a faulty thermostat, can cause gearbox problems.
The gearbox oil on these cars is NOT straight forward to change, and really needs to be done on a ramp. It has an internal tube built into the drain plug which is used to measure the level as there is no dipstick like the older cars. The process is well documented on the internet and I won’t be covering it in this blog as this is not a ‘how to’! As mentioned above we now offer the EDT system which is the best way to ensure as much of the old fluid is replaced. Cost is around £300 + VAT for this process.
If replacing the oil changes nothing or even makes things worse, then you will need to replace the valve body. This is the hydraulic control unit inside the gearbox that controls the gearbox functions. Inside it are a set of solenoids (electric magnetic devices that move when they receive an electric current). These solenoids operate the pistons that distribute the hydraulic fluid to each gear and smoothly enable the desired automatic changes. The pistons are made of steel and slide in an alloy housing, and the problem starts when the oil that’s used loses it’s lubrication effectiveness…. the pistons start too stick in their housing, causing the gearshift to delay, and as a result there’s a thump/bang when they finally move. Because of the nature of the construction of the valve body and it’s complexity, it’s actually cheaper to replace the unit, and thankfully it’s not a difficult job. We charge approximately three hours labour to replace one.
This will cure most issues, and normally will be a permanent cure, but not always.
If, after a while, the car starts to feel awkward at lower speeds, particularly when manoeuvring, almost as if you aren’t disengaging the clutch on a manual car, you may find that the torque converter is starting to wear, or the clutch inside has ceased to function correctly. A torque converter is a centrifugal clutch unit that allows the smooth change of gears controlling the “lock up” function crucial for a smooth changing gearbox.
Sadly, replacing this item is a fair task and unlike the valve body requires the removal of the gearbox assembly from the car.
We have found that once the converter is replaced it often takes some time for the gearbox to settle down, sometimes up to a month. As with all of these units, they are adaptive and learn to adjust to the individual need of the driver. We use electronic diagnostic equipment from Volvo called Vida to reset these adaptations, but usually this doesn’t immediately help. It seems even leaving the gearbox overnight can dramatically change the way it works, and we think this is because of the way the unit is initially programmed allowing it to retain certain settings even after a reset. I can imagine that sounds a bit like a load of twaddle, but in practise it seems to work.
If you would like to chat through your issues, or get some advice regarding your gearbox please feel free to me or my team a call to chat through your options.
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Graham Lange – Horton Cars