[RobLog]

Been having an intermittent P0743 code thrown that has now become constant. The torque converter is not locking up as it should and after doing the diagnostics, it looks like the Duty B solenoid aka Lock-up Duty solenoid needs to be replaced.

After reading the service manual, it doesn't look like too tough a job for a moderately experienced DIYer, but would appreciate pointers from someone who knows more about it that I do. The drawings in the manual aren't always the clearest.

After dropping the trans pan and maybe removing the screen filter, both of which I have done before, is the Duty B right there to be unplugged and unbolted? Or is there more to it, like removing valve bodies?

 

[cardoc]

Here you go. Good Luck.

Be sure to check the internal harness for cracks in the insulation that may allow for a short or open condition as they may most likely be brittle.

 

[RobLog]

Thanks for the support, cardoc. Due to an overwhelming lack of info out there on this repair, I'm not surprised at the lack of response from people here. I'll probably go ahead with it and will post results and maybe a how-to if I am successful. As our cars get older, there will probably be more people who will experience this as of yet rare problem.

 

[cardoc]

Not really. It doesn't occur much. The parts fail due to debris in the system or overheating. You will most likely find a pan full of materials. Flush it out good before you tear it down and be sure its full before you drive it.

 

[RobLog]

Well, the code indicates an electrical problem, so I don't think it is caused by debris.

Four years ago after the HGs went and were repaired, I did four consecutive drain and fills, dropped and cleaned the trans pan, and changed the screen filter. I've done a drain and fill every year since then, too. If there is a lot of debris in there, I'll be surprised. Wouldn't be the first time, though.

 

[H-D]

+1 with cardoc; all of these I've found on other makes (mostly domestics) have stemmed from hydraulic restriction at the solenoid, or at a screen just upwind of it.

 

[RobLog]

Successfully replaced the Duty B Solenoid. If interested, see the write up in this thread:

http://www.subaruoutback.org/forums/99-do-yourself-illustrated-guides/50808-duty-b-solenoid-replacement.html