Hey guys,

 

So I just got a call from my wife and she is telling me that the transmission in her Legacy keeps shifting back and forth from 3rd to 4th gear every 3 seconds or so and will not stay in a single gear on flat highway. Already being out 15 miles when it started doing this, I told her to put it into 3rd gear manually and just take it easy, but she's saying the car is pretty much undrivable when you put it in D.

 

The car has 96k and there are no transmission warning lights on at all. I have driven the car many times and while on hilly terrain I wish the transmission was more responsive, I haven't felt like anything was functioning out of the ordinary.

 

Any thoughts?

have you changed spin on fillter ? any dents in pan? and does it hesatate when puting into gear first time cold or hesatate when puting in reverse also dose speedo work properly and cruise ? also check main harness ground bolt on ps top of intake is clean and tight this is also your trans ground

is there a flashing AT TEMP light on the dash.??

 

i had both symptoms and it was a loose ground wire on the engine.

simple fix, but very hard to identifdy.

 

check for loose wires bolted to the engine, mine was near the coil, passenger side.

Edited June 12, 201312 yr by johnceggleston

Could be a TPS (throttle position sensor) malfunction.

 

Any check engine codes?

No CEL or flashing lights at start up. Once I get the car back home, I'll get back to you guys with more info. The car has a perfect maintenance history through the dealership since new from its previous owner and all I've done to it is a timing belt kit...

 

I'm just hoping it's nothing too serious.

I cannot find anything out of the ordinary. I was able to get the service records from the previous owner since they bought it new at the Subaru dealer I buy parts from and had all work performed there.

 

Never missed a service and the transmission was serviced at 60k. They did a flush and fill with a new filter...

 

The only thing I did before the tranny started acting up was switch the oil from 5w-30 conventional to 5w-40 rotella t6. When I first got it, since the dealer only replaced the timing belt when they replaced the head gaskets because they were leaking, I put in a new timing belt kit because the idlers and tensioner weren't done. The service records note that the head gasket on the passenger side was weeping, but they didn't feel like it was a big enough deal to replace them.

 

Hasn't acted up since that one time, but I do notice that the tranny seems to run in too high of gear when going up hills. I just tap the accelerator to get it to downshift, but nothing else feels out of whack.

 

I was thinking doing a drain and fill a few times with Amsoil ATF. Do you all think that's warranted at this point? I have had my Outback with a 5MT for like ten years and another 93 legacy with a 4EAT, but it never gave me problems. I have absolutely no experience with these things so any advice is very much appreciated!

i'm doubtful a fluid change will help at all, but i suppose it's worth a shot.   i would definitely check the fluid level and look at it and smell it.

 

i'd lean towards swapping the TPS, should be able to get a used one for only a couple bucks.  they're super easy to replace and rarely fail so not worth price of new.  the H6 vehicles have quite a few TPS failures in this same year, not the H4's but it's possible.  if i could find the used one i have i'd send it for a few bucks, as it is i don't have time to look for it.

Check main trans conectors are pluged in all the way and check air preshure in tires have seen a low tire confuse the trans ecu