Subaru Outback torque converter?

Over the last several months, the frequency with which my 2007 Subaru Outback is “shuddering” when I accelerate from a stop has been increasing. It feels like driving over a cattle grate – a vibration that lasts for just a few seconds, and occurs in the 35-45 mph range. Now is happening on a daily basis, a couple of times per day. Based on some internet searchers, I concluded this might be a torque converter problem. Took it to the mechanic today and, of course, couldn’t reproduce the problem with them present. They replaced the transmission fluid with a synthetic fluid and replaced the transmission filter. Any other thoughts on what the problem could be and/or how to best address it? What should I be aware of?

The speeds you mention is the speed the lock-up clutch in the torque converter activates. If it is going bad, it will cause a shudder. The only fix is to replace it. However, other diagnostics need to be performed to rule out contributing factors, like a bad solenoid or lack of fluid pressure. The fluid change may just help the problem, but I doubt it is a solution.

There’s always the possibility that this could be an engine performance problem also; maybe related to a MAF sensor, vacuum issue, etc.

Does car drive any better with trans service?

Hard to say as of yet… I did feel the sudder once on the way home from the shop, but the mechanic told me I should drive it for a week or so before determining whether or not it’s ‘fixed’. Didn’t feel it at all on the way to work this morning, and typically that’s when I have noticed it the most.

Anyone happen to have a rough estimate of how much you’d expect it to cost to replace the torque converter? Can one just replace the lock-up clutch? Any other ‘signs and symptoms’ I should keep an eye out for, beyond just the shudder?

Thanks very much for the replies.

I am having the identical issue with my 2010 Outback. It is at the dealership today and they are trying to determine if it is the torque converter or not. Apparently they think it is. Lucky for me it shuddered really hard a couple times when the technician drove it. I’m wondering if your problem has been resolved or not and where things stand now? Thanks

It sounds like you are on the right track OP. I’d guess it is a TC shudder problem. Even new they shudder a little bit, but yours may be shuddering more due to some wear and tear. Evenutally you’ll probably need a transmission rebuild. There are parts that wear out over miles driven in any automatic transmission. Needing a transmission rebuild from time to time is like needing to change the brake pads when they wear out. Or a clutch replaced. It’s expected maintenance. Only more expensive. Replacing the fluid and the filter is a good first start. It could well solve the problem. If it seems to improve the situation, consider to have the fluid changed again. It’s difficult to completely replace the fluid in just one change, some always remains. One caution: you must be absolutely certain the fluid the shop used is one recommended by Subaru, and meets all the Subaru specs for your vehicle.

Thanks for all the feedback. For those who are interested – over the last 5000 miles or so several things have been done, and now I no longer am experiencing the shudder (knock on wood). The transmission flush and relearn didn’t seem to help much, but I noticed the biggest improvement after getting the 90k mile service (which included replacing spark plugs) and using some fuel system cleaner. Not sure what did the trick, but it has been 2 weeks now since the 90k service without the shudder (which had been happening daily)…

Thank you for the follow-up. If the spark plugs were the originals then it’s quite possible that was the cause of the problem considering the mileage.