5EAT Transmission Woes

[Flatfour02]

Hello all. Having some trouble with the Subie. A while back, my 05 XT started to develope torque steer.  It got gradually worse until it seemed like the car would all but stop when I turned the wheel.  I saw a spare 05 Outback XT Trans on Facebook marketplace for $100, so I figured I'd give it a shot since it was so cheap. Got it in, and things aren't going well. It has a trans code (p700) on the accessport, but can't tell what the specific code is.  What I can see though, is when the car is sitting in park, or neutral, I can see the drive shaft spinning. Never had that issue before, so I'm assuming this transmission is junk. I'm also now a bit concerned with the rear diff, as it is being spun by the transmission while the car is sitting still in park.  Does that indicate the rear diff is bad as well? Also, what are my options for replacements? I know the 05 XT does not share a FD ratio with any other year or model, but if I replace both the transmission and rear diff, could I use a set from a different year? I appreciate any help I can get with this. Thanks!

[silverton]

P0700 is an ECM code triggered by the TCM, to let you know there is a DTC in the TCM.

[KZJonny]

14 hours ago, Flatfour02 said:

but if I replace both the transmission and rear diff, could I use a set from a different year?

Yus. Can do, but as noted you need the trans and the diff. There may be some TCU issues between the different phases of the 5EAT, but I am sure I've read about them being worked around. I think 05/06 were both phase 1? So, even if they have a different FD, they should talk to the ECU the same way. (I think the full CAN system in the later years causes problems)

[Flatfour02]

I know there is a list somewhere in the forums that details all of the different transmissions for all the different subaru models. Haven't been able to find it recently though

[Flatfour02]

Maybe a more specific question.. should I replace the rear diff before deciding the transmission is what is bad?

[silverton]

On 11/20/2023 at 1:14 AM, Flatfour02 said:

 What I can see though, is when the car is sitting in park, or neutral, I can see the drive shaft spinning.

 

This is with all four wheels on the ground?

[Febreze Mee]

@Flatfour02 maybe these could help?

https://legacypic.uk/transmission/

https://www.gearhack.com/myink/ViewPage.php?file=docs/Subaru Transmission Chart