Got a code 79 on my 01 Subaru Legacy sedan, auto, 155k miles. The "AT OIL TEMP" light blinks and stays blinking once started on a cold morning, and the car seems to have torque bind. Low speed maneuvers feel like all four tires are flat, the awd is fighting. The "subaru secret handshake" displayed the code, 7 long blinks followed by 9 short ones, which translates to this solenoid - most of the time. Going out to lunch or driving home, the light stays off and the torque bind seems to have disappeared.
So I went to the dealer to order the parts, and the parts guy said "well, you might as well try changing the ATF and filter first". If that doesn't do it, he said I should do the solenoid and the clutch packs... about $300 in parts, and a whole bunch of time. Alternatively he said I could install the FWD fuse.
Does anyone have experience with this? Am I nuts to pray that a fluid change will make it go away?
Secret handshake:
http://forums.nasioc.com/forums/showpost.php?p=790395&postcount=5
The job in question:
http://forums.nasioc.com/forums/showthread.php?t=2501432
That's a "detect slip, apply clutch" system, right? It sounds like a question of what's sticking and leaving the rear axle engaged, and why. Maybe it's just a bit of gunk in the solenoid that fresh fluid will take care of. I'd do a fluid/filter change, Valvoline maxlife is good stuff, just for E36 M3s and giggle first, and put the FWD fuse in until the issue is resolved. Seeing if putting the fuse in actually locks it out of 4WD would probably be a good test too.
Service the diffs while you're at it.
Yes, putting in the fuse is a good test. If the solenoid is truly broken then the fuse will have no effect.
I've also noticed my gas mileage has been horrible for a few weeks. Apparently that is also a clue.
This is a pretty common problem with a long-lived 4EAT from what I can understand. They must get plugged up with magical automatic transmission sauce gunk or something.
There are some duty cycle parameters that get exposed through SSM if you have the ability to run FreeSSM against the car. I bet if anything is wrong with the solenoid you'll see something crazy in there.
When the auto trans went out on my higher mileage '05 Forester winter beater, I found that 100,000 mile used units were all over the place around me (in SW, Michigan).
I ended up with a 115,000 mile trans with a 1 year warranty for $180 through a parts recycler I found on car-part.com.
It was surprisingly easy to change. The only problem I had was the freakin exhaust just fell apart when I removed it. Full cat-back exhaust system was only $160 from Rockauto.
I have an 04 2.5rs/Auto that has been having trouble and I have discussed it with a friend who is a subaru dealer tech.
On the highway if I put my boot in it and make it downshift to accelerate the trans will freewheel on the change then engage very abruptly (kinda violently, makes me worry that its gonna break itself). I have been driving around it for ages, but not being able to accelerate rapidly from a steady state is very annoying.
I also have a clunk going around tight turns that he said was interrelated (and we have checked all the CV joints)
Other then that it just seems to have sluggish response.
From what my friend told me I should just go for a "BG" transmission flush as that is the best one they have found for them. Plus a filter change. I still need to make it happen on ours and the backup is swapping the trans (which with some of the rust on the car I am starting to think just means to bail and get another car).
My son works for a Suby dealer in Memphis.....they HIGHLY recommend BG conditioner when performing trans service on Suby AT. My light came on on my 99 Impreza with 4EAT at 100K. Found leak in cooler(radiator) had slightly contaminated fluid. Replaced radiator, flushed lines, performed trans service, replaced filter and added BG conditioner. No worries or lights since.......
Interesting, two recommendations for BG. I've never even heard of that until I read this post. Thank you
I put the FWD fuse in this morning, no blinking lights. I am not sure if this is good news or bad news.
I also picked up two gallons of Castrol ATF. I know I'll only get a few quarts out at a time since most of it will get stuck in the torque converter, but two gallons should let me drain and refill multiple times.
I changed the fluid and filter yesterday for the first time. Wow, it was disgustingly dirty. It looked and smelled more like used motor oil then ATF, yuck. Remember to do your maintenance, boys and girls!
I removed the FWD fuse and now I'll see if the issue returns.
In that case, you should probably do it again sometime in the near future if you only did a drain and fill.
I have fixed a suby trans with TRANS X, did a drain, new filter and fluid with a full can of it. Worked great. I will try the BG flush on the next victim, and see how it works.
