We should be back to normal schedule tomorrow.
Volvo TF80 (AWF21) Transmission Issues
A few months ago, I bought a very nice 2007 XC90 V8 Sport. Soon after buying it, I started having transmission shift flare issues which ultimately led me on a quest for knowledge. I found lots of people on forums having issues with the transmissions in these cars but the opinions on the problem and solution were all over the place.
A little background:
- XC90 models were available with the V8 option around 2005 onward.
- S80 P3 models were available with the V8 option from launch in 2007.
- All Yamaha V8 AWD models are equipped with the TF80. Some other later P3 models also got the TF80 with different engine packages.
- The TF80 is a 6 speed automatic transmission manufactured by Aisin Warner.
Variations of this transmission are used by a lot of different car manufacturers, but Volvo seems to have more problems with it than others.
Many people on forums were complaining that the TF80 is not strong enough for the V8 equipped models and “Volvo should have known better.” While it is true that these transmissions do have plenty of problems, it’s not due to lack of strength. It is rare for these transmissions to have any sort of real mechanical damage or to actually be worn out.
I contacted various Volvo specialty and transmission shops in the Portland area and discussed issues they see with the TF80. Most of the shops confirm that they rarely see a TF80 actually fail to the point that they need to be rebuilt. Most of the problems with these transmissions can be solved without even removing the transmission from the car.
- Make sure the Transmission ECM has the latest Volvo software. This must be done using a Volvo VIDA station.
- Make sure the transmission fluid is clean. Flush if in doubt.
The most common issues with these transmissions is “Shift flare” and hard downshifts.
Shift flare is a condition that occurs on up shifts between a lower gear and a higher gear. The transmission will simply shift out of the lower gear and delay before engaging in the higher gear. This will result in the engine RPMs “flaring” (revving high) prior to engagement in the higher gear. It seems to be more common with lower gears but can happen with any of the shifts. Typically, the transmission will start exhibiting the symptom between the same two gears. Early on, this may only happen randomly once the transmission is warmed up but as it gets worse, it may happen consistently at any temperature.
Hard down shifts are basically the same problem but there usually isn’t an engine flare associated with it since your foot isn’t on the throttle. They are most noticeable when coasting to a stop. You’ll notice the transmission “thunking” in to lower gears. Sometimes when applying the throttle after almost coming to a stop, you will get a harsh gear engagement but without significant an engine RPM flare.
The most common shift flare is between 2nd and 3rd gear but the issue can occur between any gears. The flare may not occur consistently but will consistently be between the same two gears. In other words, you may intermittently get a flare but it will always be between 2nd and 3rd.
A shift flare followed by hard gear engagement while under heavy engine load that can break (i.e. crack) internal mechanical components. This should be avoided. A quote from a transmission tech: “You only get to do that once or twice then we have to rebuild it.”
So what causes this shift flare? Quite simply: A worn out valve body.
A low fluid condition could also cause weird shifting issues but you checked that when you flushed the transmission fluid right?
The valve body on the TF80 is a complex looking component with an internal maze of oil passages and a handful of moving parts. There are a series of piston valves connected to electronic solenoids that control where the fluid pressure is directed within the transmission. The primary failure point is that the steel pistons eventually wear out the aluminum piston bore and let fluid leak around the piston. In some cases, they don’t wear out but get sticky from dirty transmission fluid. These pistons are controlled by the transmission Control Module and pulsed (duty cycle) to control the pressure and finely control shifting. The pulsing action causes more wear and tear on the piston bore. Dirty transmission fluid will make this wear happen much faster.
Replacing the valve body will solve 99% of the shifting issues with these transmissions.
A skilled Volvo technician (or an experienced Transmission Tech) can replace the valve body without removing the transmission from the car but it’s still an expensive repair.
From my research, good rebuilt or aftermarket valve bodies do not exist. Sure there are a bunch of companies offering them but to rebuild one of these correctly will cost as much as a new unit from Volvo. In fact, the shops in our area all buy valve bodies straight from Volvo dealerships. New seems to be much better than any rebuilt options at this point.
I’m being told by local shops that it is not uncommon for an XC90 primarily doing city driving to wear out a valve body in less than 80,000 miles. All that shifting works those valve body pistons that much more.
So basically, if you have a Volvo with a TF80 transmission, chances are that you will probably put a valve body if you own it for more than a few years.
It becomes very obvious that transmission servicing (fluid flush) is very important for extending the life of the valve body in these transmissions. How much longer really is the $1000 question. It will certainly help to keep the valve body pistons lubricated and not have abrasives in the fluid.
I’m also told that worn out torque converters are not uncommon (which does require transmission removal.) The local shops all blame Volvo’s aggressive software for this issue. Volvo designed the software for fuel mileage, not transmission longevity so the lock up function in the torque converter is being used far more than normal in lower gears. They just want less slippage since it adversely affects fuel economy. This issue is more apparent with vehicles that are primarily used for city driving or vehicles used to tow a trailer.