Ask an expert

Hi. This is less of a question, and more a case of information to others with similar vehicles.

I have suffered for a few years now with the (5-speed automatic) gearbox in my Outback 3.0 exhibiting significant shift-shock when changing down during braking. Note, this is not an accelleration-driven downchange, but a slowing down downchange.

This shft-shock ranged from a slight tremor, through to quite significant banging that could be felt (and heard) through the steering and drive-train. I took the car to several 'specialists', none of whom got even close to diagnosing the problem.

I took it to the local dealership twice. The first time no joy, but thanks to the attention of Sean, the head mechanic at Armstrong Subaru in Wellington, we found out that there is a software update to fix this exact problem. The problem was that this software update was listed in the Subaru LEGACY update list instead of also being in the Subaru OUTBACK update list.

I have had the update applied to my car, and the problem has not resurfaced since. I went for a drive for about 2 hours over the weekend, a mixture of motorway and suburban, with several stops and varying speed. This would normally have caused the problem to exhibit itself but it did not.

I recommend any other Outback owner who has noticed similar behaviour to go to the Subaru dealership to have this update applied. Just be sure to tell them that the update is in the Legacy lists...

Our understanding is that the Legacy and Outback have different software due to different differential ratios. It's good to hear that your dealer has finally been able to find a solution for you.

Hi. Just spoke with the mechanic at Armstrong again. Two points:

1) There isn't always a differential ratio difference. There is a difference in tyre sizes which makes for a different rolling ratio but that isn't the same as a different differential gearing.
2) The software physically won't install if it isn't compatible with the gearbox. At install time a check is made to ensure the gearbox model is compatible with the software update and the only way that it will complete is if the update list includes the model gearbox the update is being applied to.

I can say that I have not detected or noticed any change to the feel of when gear changes are made. So the engine isn't revving higher or lower than it was before.