I have a '03 GT Legacy sedan, if it is in Drive the car jerks bad when doing around 45-50 mph.  I can't tell if it is the torque converter locking and un locking or a 3rd to fourth mis-shift.  I have put full synthetic ATF with Wix filter in the 4EAT Transmission last swap.

no AT light blinking at start up?

check engine lights?

 

H6's of that vintage have TPS issues that cause erratic shifting and don't always throw a CEL.

 

above and below that speed it works fine?

no lights, no flashing.  It is a EJ25 so don't know if H6 issue would arise.  It is mainly if you are coasting and slightly apply gas again around that speed.but will do it + or - 10 mph of 45.

I am going to try draining and refilling the ATF again with a Subaru tranny filter.

I drained the pan, removed the spin on filter and got another 2 qt.s out.  Replaced the spin on filter with a genuine Subaru ATF filter, refilled with fresh fluid and still having the shifting issue.  Anyone ever used Lube Guard in our transmissions? I am not a big believer in additives.  But OE manufactures approve of this one, and my local tranny rebuild shop uses it.

and you've tried other gears? you should be able to put it in 2nd or 3rd and see if still happens....not sure What it tells you, but may narrow it down. And you're 100% sure the level is correct? ATF level in 4EAT is a pain to get 'just right'.

 

And I agree w/the possible TPS - h6 or not. Find the FSM and test your TPS.

 

Td

Edited November 21, 201510 yr by wtdash

It does not do it if I use the manual mode the GT has or 3 in the selector.  So the tranny is trying to go into OD/4th to early all the time.