Transmission problem
2003 Subaru Outback 6 cyl All Wheel Drive Automatic 62000 miles
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When I start uphill from a stop, the auto transmission seems to not be in 1st gear; I have to pump accelerator to convince it to down shift and move the car faster than a crawl. Similar problem at speed, but not consistently - and occasionally I feel a shudder as the transmission comes in and out of top gear at 40 - 50 mph. At 60K the fluid was changed. The shop just had the car a full day, and "didn't experience the problem" - but leaving the shop - I couldn't get up the hill from the parking lot until I stomped on the gas. With this low mileage, I shouldn't need a new tranny... could this be a vacuum problem?

Hi weedlawn,

Thank you for the donation.

Kindly check if the following helps.

ON-BOARD DIAGNOSTICS SYSTEM FUNCTION

The on-board diagnostics system detects and stores in the form of a code a fault that has occurred in any of the following input and output signal systems.

If a fault has been detected, the system tells the fault by causing the AT OIL TEMP warning light to operate as follows: 
1. Repeated flashing at 4 Hz frequency ... Errors such as battery trouble 
2. Repeated flashing at 2 Hz frequency ... No faults in the system 
3. Flashing at different intervals and frequencies ... Diagnostic trouble codes of corresponding faults 
4. Continued illumination of light ... Fault in inhibitor switch, idle switch, or wiring

OPERATION OF AT OIL TEMP WARNING LIGHT On starting the engine, the AT OIL TEMP warning light illuminates and then goes out as shown in the "Normal" diagram below. If any problem exists, the warning light continues flashing as shown in the Abnormal diagram below.



Operation Of At Oil Temp Warning Light - Normal & Abnormal Diagram Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC TROUBLE CODES DIAGNOSTIC TROUBLE CODE
DTC Faulty Component
11 Engine speed signal circuit
27 ATF temperature sensor
31 Throttle position sensor
33 Front vehicle speed sensor
36 Torque converter turbine speed sensor
38 Torque control signal circuit
45 Intake manifold pressure signal circuit
71 Shift solenoid 1
72 Shift solenoid 2
73 Low clutch timing solenoid
74 2-4 brake timing solenoid
75 Line pressure duty solenoid
76 2-4 brake duty solenoid
77 Lock-up duty solenoid
78 Sports shift solenoid
79 Transfer duty solenoid
86 VDC communication
93 Rear vehicle speed sensor

AUTOMATIC TRANS - MECHANISM & FUNCTION -2003 Subaru Outback 9/5/2008 http://www.ondemand5.com/mric/common/asp/printart.aspx

The AT light functions normally - no error code. The problem is worsening, though, with the transmission more and more often failing to downshift to accelerate. It's hazardous to pull into traffic.

Hi weedlawn,

Since there are no error codes, you need to check the engine performance related items.

1. Throttle Positioon sensor.
2. O2 sensor.
3. Ignition timing.
4. MAP sensor.
Was any repairs/adjustment done prior to this happening?

Thanks - appreciate it. The car had its 60K service about two months ago, but this didn't start until last week.