Outback transmission problem

Tiny
CHRIS MARCOS
  • MEMBER
  • 2000 SUBARU OUTBACK
  • 4 CYL
  • AWD
  • AUTOMATIC
  • 100,000 MILES
I have a 2000 Subaru Outback with about 100,000 miles. I don't ever
have a problem with the Reverse, but once every month or so, I would
get a no-drive condition with all Forward gears (D, 1, 2, etc.).
It is as if the transmission is still in Neutral. I press the gas,
the engine revs up, but the vehicle does not move forward at all.
Eventually, the vehicle would move again after I've frantically
shift through all the gears over and over again. Please be as
technically detailed as you can in your explanations of possible
root causes. I've studied a book on automatic transmissions and
am familiar with valve bodies, clutch packs and clutch apply pistons,
torque converters, overrunning clutches, etc. The fluid and filter
have been changed regularly (and recently) and the fluid's current
level is good. Thanks.
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Tuesday, March 29th, 2011 AT 5:22 AM

5 Replies

Tiny
KHLOW2008
  • EXPERT
Symptoms indicates a fault with the control valve, an intermittent fault with the valve body. Most likely you would need to remove the valve body and service it. The control valves could be sticking intermittently.

Have you tried retrieving for trouble codes?
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Tuesday, March 29th, 2011 AT 12:10 PM
Tiny
CHRIS MARCOS
  • MEMBER
I checked with a scanner, and there were no trouble codes stored.

I researched the Internet for similar problems and discovered some reports indicating that this might be a common problem with 99-00
Outbacks, Foresters, etc. They point out a problem with an internal
seal of a clutch that is allowing a fluid bleed-down.

Here is one typical comment:

"the fault with your hesitation from park to drive is from a worn piston seal on the fwd clutch pack. The time lag test should be no more that 1.5 seconds from park to drive/reverse. If you apply the throttle you are producing greater line pressure to overcome the lack of pressure in that clutch pack. Then when it does apply the clutch pack with throotle you will get a shift shock. Rebuild if you know your dealer tech is confident in trans rebuiling or just get the reman unit."

If this is indeed the root cause, do you know if it is possible
to change this seal without removing the transmission from the vehicle?
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Tuesday, March 29th, 2011 AT 4:09 PM
Tiny
KHLOW2008
  • EXPERT
No, this means a transmission disassembly, similar to a rebuild.
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Tuesday, March 29th, 2011 AT 6:20 PM
Tiny
CHRIS MARCOS
  • MEMBER
I've always been scrupulous in performing the recommended
maintenance procedures on the transmission, so I'm surprised
to learn that any seal would be worn. Is it possible that
my problem is not due to a worn seal, but instead due to an intermittent failure of the solenoid that activates the valve
which feeds fluid to the clutch?

I recall sitting at a traffic light one day, and I could feel one
slight shake of the car, as if it was disengaging and going into
Neutral by itself. When I pressed the gas, the car would not move.

How can this be caused by a bleed-down through a bad seal if there
is always be pressure on the line supplying fluid to that clutch
piston (assuming the appropriate solenoid remains energized)?

Is there a quick and easy test that can be done to determine
whether it's really an intermittent electrical problem that might
be fixable without a transmission removal and overhaul?

Thanks very much for your advice!
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Tuesday, March 29th, 2011 AT 7:59 PM
Tiny
KHLOW2008
  • EXPERT
Seals can cause such faults as they wears and hardens over time resulting in leakages no matter how maintenance was done.

When solenoids fails or there is an electrical fault, they would usually trigger troubles codes and the transmission would go into "LIMP MODE". Checking the solenoids and valve body does not require removal of the transmission. It is the best way to start with and my opinion is that a sticking valve or pressure leakage is the most likely cause.
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Wednesday, March 30th, 2011 AT 10:15 PM

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