Tranny Issues

[lgtPR]

Hi

My car Legacy GT 5eat has been weird. It runs and at some times you can hear a clank sound on the back part and the car shifts to a higher gear. usually happen when shifting from 1 to 2. Scanned the car and had the following codes P0817, P0756, P0766, P0763 and P0700. if i turn the car off it works again fine for a little time. I havent used the car for almost 2 years now and i want to fix it.

Car had Mobil 1 AT oil and is full.

[whitexc]

The first no no is the Mobile fluid. Was a complete flush done to get that fluid in or is it mixed with the OEM, recommended fluid? Idemitsu HP is what should be in the transmission.

 

Google the codes. Sounds like you have a few issues to address. An engine related code could lead to running issues and shifting issues.

 

These transmissions are known to have a few quirks in my short time being involved here. There is a failure that occurs with a hall affect sensor (speed sensor 2) attached to the valve body. It is associated with hard shifting. There are walk throughs out there explaining how to replace this. It doesn't look like a horrible job with dropping the valve body and doing some soldering of wires. It's on my list of to do's.

 

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[lgtPR]

Fluid is mixed. Like 3 mobil 1 quarts.

Would you reccomend a flush before anything else?

[Pleides]

A flush would likely help a fair bit with rough shifting if the fluid is original. Some people will tell you flushes are bad for your trans, but I've never seen anything substantial to prove this and Subaru doesn't advise against it. Manufacturers usually explicitly state not to do it if they don't want you to in automatics. There are 8 or so quarts throughout your transmission that didn't get replaced and changing out three quarts is a drop in the bucket.

[whitexc]

I would only advise a flush if it were done by a subaru shop/stealership that stood behind it. Depending on the miles it can move sludge and debris through the system that was there prior but not necessarily in a bad way. Start getting that junk in the valve body and you are asking for trouble.

 

I would do drain and fills with OEM fluid. There are plenty of walk throughs on the interwebs. If you can unhook the cooler lines and push fluid out in measured amounts and replace it with fresh at a controlled rate you will get it all within a few cycles.

 

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[captainobvious]

i would also suggest getting a new atf filter and replacing that, if you have no idea when if it was replaced last, i would replace that as well as doing a drain and fill on fluid. Word to the wise ive done my 5eat twice and only use Subaru OEM fluid.

[lgtPR]

Ok will order fluid now and the filter and report back. If it stills with issue which step would you take?

[whitexc]

Order a VagCom cable off eBay, download FreeSSM and perform a reset on the transmission TCU. If it still acts up it may have issues.

 

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