'99 Legacy GT wagon 4-3 downshift problem

[mwatt]

My '99 Legacy GT wagon with the 4EAT has developed a 4-3 downshift problem: when you need to force a 4-3 downshift to merge onto a highway, the engine will "flare" for a split second, then the transmission slams hard into 3rd gear---sometimes so hard it chirps the tires. Maybe if I were still 18 years old, that'd be cool...but I'm way past that stage....

 

No "check engine" light coming on. No "AT temp" light coming on. Transmission UPshifting is flawless--cold or warm---and there's no "delay" going into gear when cold. I've changed the trans fluid (and that damned $30.00 spin-on filter that Subaru claims "never needs replacing") so many times, I've lost count. Making matters worse, the problem tends to vary...there is not a repeatable pattern to this.

 

I'm thinking a shift solenoid is failing, or sticking. Anyone concur?? If so, which one would you try replacing?

[canthony15]

I have been digging for an answer to this symptom for weeks now. I bought a 99 30th anniversary Outback wagon that does the same thing. Everything is good except 4-3 downshift which gives a flare and a slam. If I downshift manually, no problem. Tranny was flushed not long before I bought it (they had the shop receipts). It is full (I checked it).

 

I think I have read every post there is about the 4EAT downshifting. I have found a handful of folks describing the same symptom, but there are never any followups.

 

I did find a second generation transmission document from Subaru that describes the 4-3 downshift sequence. Two solenoids are involved, the line pressure solenoid and the 4-2 brake duty solenoid. That's all I have found so far that gives me any insight whatsoever and that isn't much.

 

I fixed my intermittent speedometer and had the battery disconnected for about an hour. When I put it back together the slam problem seemed to be much improved but it came back in full force after a day or two.

 

BTW, the slam only happens when I start to climb and I press the pedal to try and maintain speed. Down hill or slowing down never slams.

Edited March 12, 2012 by canthony15

[markjw]

Reviving and old thread here but I have the exact same symptoms with a 2004 Forester. I also changed out the fluid and filter with little or no change. Did you guys come to any conclusion as to what was wrong with your trannys? Maybe someone else can shed some light?

[presslab]

Those symptoms are commonly called a "slip-bang" shift. This occurs when the clutches "slip" more than the TCU expects, during a shift. After the TCU decides the shift should be over, it applies a lot more line pressure, then causing the "bang".

 

If there are no codes, it's probably not the solenoids. If the fluid is old, it's probably too late to change it, and doing so will likely make it worse. Could be a clogged valve body, but unlikely.

 

A rebuild with new frictions is the fix, but one of those miracle additives (friction modifier) might buy some time.

[markjw]

Thanks for the reply. The car overall shows signs of typical neglect. Tranny fluid was a couple quarts low before I changed it. I'm thinking after the person who owns this car pays for repairs, they might then pop the hood occasionally and chk the fluids. But, then again, maybe not.

[Rooster2]

Thanks for the reply. The car overall shows signs of typical neglect. Tranny fluid was a couple quarts low before I changed it. I'm thinking after the person who owns this car pays for repairs, they might then pop the hood occasionally and chk the fluids. But, then again, maybe not.

Lots of drivers out there that just add gas and drive. If something breaks, they fix it, but don't do any maintenace work. I think we are talking the same language, when you mention "signs of neglect."

 

Prolly best to look all over the car for sign of neglect that need attention.

 

I would change the tranny fluid three times, see if this improves things. If not, maybe need to swap in a used tranny.