I have a 91 legacy with a 4 speed auto trans. I had the tranny put it not long ago and it worked great for a couple months. Then one day just like someone fliped a switch it only has 3rd gear and reverse. And when its cold and your going down a hill over 40mph it fells like it keeps jumping into reverse. Could this be a shift cellinoid? My tranny fluid is clean and no burnt smell.

Welcome to the USMB.

 

Does the power light on the dash flash when you start up the car?  If so, the TCU is indicating there is a code stored.  Either way, I'd recommend checking to see if there are any codes stored in the TCU.  Instructions to pull the codes are on my site.

 

http://www.surrealmirage.com/subaru/trans.html

Power light does nothing when i start but i will check the codes anyway. Thank you for the info!

Does the power light illuminate at all?  It should come on steady with the key in the ON position, but engine not running, should stay lit for a few seconds after startup, and then turn off.

No. The power light does not come on at all.

3rd and reverse only means that the transmission computer isn't working. No power light confirms it. Check the fuses, the harness plugs by the trans, and the plugs at the trans computer.

Where is the trans computer?

And what fuse woupd it be?

The TCU is located on the a pillar(door hinge)  behind and to the right of the glove box.

All i found to the right behind the glove box was the cruise control box

sounds like you sheared the end of the band off or smoked the forward clutch pack are you shure its not defaulted into 3rd ? default is 3rd and reverse only

The tranny was just installed before i got it from my dad. What do you mean defaulted into third?

Check fuse 14 labeled EGI/TCU.

 

Here's a listing of the fuses and diagram

 

http://www.main.experiencetherave.com/subaru_manual_scans/1990_Legacy_Owner_Manual_Scans/118.jpg

http://www.main.experiencetherave.com/subaru_manual_scans/1990_Legacy_Owner_Manual_Scans/119.jpg

 

 

The TCU is under the driver's kick panel.  This picture is looking just under the left side of the steering column

 

http://www.main.experiencetherave.com/subaru/images/ecuhide.jpg

Ok i found both thank you. The fuse is not blown i even put a nrw one in and still nothing. Plugs at tcu seem ok. Now what?

Okay, you should check that the TCU is actually getting power to it.  With the key on, check that terminals 14, 1, and 6 have around 12V with a voltmeter.

 

If the voltages are good, maybe your TCU is bad.  Get one with the same letter code on the outside; yours is probably an "EE" code.  The 90-91 Legacy had different gears in the transmission and the TCU needs to match it.