I have a 1991 Subaru Legacy L with the standard 4-speed automatic transmission with lock up. Duty solenoid B within the transmission is responsible for the lock up however it's been failing or not working at all for a little while and when it does work it is weak. The transmission could probably use a good flush but I don't know if that would solve my problem at all Maybe the weak problem but I'm not sure if there is a short or something causing the transmission to not lock up or if Duty solenoid B is just dead.

Hi,

If the 4EAT and/or the Duty B is dying there may be codes stored in the TCU - trans computer. Does the POWER light flash when you initially start it?

TD

Hi,

If the 4EAT and/or the Duty B is dying there may be codes stored in the TCU - trans computer. Does the POWER light flash when you initially start it?

TD

Yeah, that's how I figured out what it was. And then learned more when I had time. It flashes a code corresponding to duty solenoid B.

Edited June 23, 20178 yr by Ubatz

What condition is the fluid in?

What condition is the fluid in?

Last I checked it was starting to get a bit dark cause I thought I smelt it Burning. It does have that smell on rare occasions. Usually on Long trips

Drain and refill two or three times (driving a few hundred miles between drains).  I like Valvoline MaxLife ATF.  Solved a harsh shift problem in my 99 OBW.  I also had a similar issue (no Torque Converter Lockup) that ended up being the ATF Temperature Sensor.  They had to replace the Transmission wiring harness inside the transmission.  Was not a cheap fix!

Drain and refill two or three times (driving a few hundred miles between drains). I like Valvoline MaxLife ATF. Solved a harsh shift problem in my 99 OBW. I also had a similar issue (no Torque Converter Lockup) that ended up being the ATF Temperature Sensor. They had to replace the Transmission wiring harness inside the transmission. Was not a cheap fix!

Thankfully my transmission isn't as complicated with the temp sensors. However, you could be right. I'll get it flushed and taken apart and cleaned. Then I'll have them check the wiring if that doesn't work after a little bit. it DOES have 300k miles

If you have a code then it's likely not fluid related.

 

That said Is change the fluid just because it

needs it anyway.

 

Those 91 era legacys were part of a transmission recall due to a specific issue, I think they install an external cooler or filter. Check into it and see if your car was subject to that issue and fix.

 

Check the transmission pan for dents or damage. The solenoid is very close to the pan so if the pan gets damaged the wiring can get damaged, the connector/top of solenoid smashed or solenoid broken.

 

If it's just a solenoid failure then drop the pan and swap in another solenoid. They don't fail very often at all so used is odten a great option.

 

If you smell an odor after driving then that's probably not transmission relatedness. you're probably leaking oil or PS fluid or slinging grease from a cv boot onto the hot exhaust. Track that down and repair it.

Edited June 26, 20178 yr by grossgary

I know I leak a little grease and that's getting fixed this Wednesday. The solenoid works sometimes but mostly not. It works on hot days abd I figured that would be because the fluid is less dense from the heat. Cause gear changing had become sluggish as well. [i work a part time job at 17 and am an aspiring mechanic. So flushes aren't easily in my budget.] I was recommended that it might just be a short. The pan looks undamaged but I'm gonna have it inspected. It's hard to find the part on my own so I may leave it to them.