Changed transmission fluid in '95 Legacy S

[Stelcom66]

I changed the oil and automatic transmission fluid in my son's '95 Legacy S today. The owner's manual called for 8.3 quarts of Dextron fluid. I drained and added maybe about half that amount - so it didn't completely drain. Seemed like the dipstick reading read normal with only about 3 quarts, but added another anyway. It's been a long time since I drove it - I don't recall what the rpms should be at 65 mph. I know it needs to be at a certain temperature for the torque converter to lock up. I think that occurred, after a while at 65 the tach read about 2700 rpm. Seems to be in the ballpark. My '02 Outback automatic was 2600 rpm, my '02 Forester manual is 2750. The '95 Legacy is running well at 177+K. Does 2700 rpm at 65 mph sound about right?

[Ibreakstuff]

2700 @ 65mph sounds great for gas mileage.

You can't expect to get all of the auto fluid out during a simple drain, the amount will vary car to car also (I have no idea why).

Get the car is running/warm (20 mins) and cycle through each position and check the fluid again (neutral on flat ground). You don't want to overfill either.

[nicholi2789]

I work in a lube shop. 8.3 quarts is the TOTAL fill capacity for that automatic transmission. In other words the entire system. Newer Subarus take about 10. When you just pop the plug on the transmission pan and drain it, then fill it again, you usually only get about 30-40% of the fluid as there is still fluid left in the transmission cooler, lines, and torque converter. That's why a lot of places use a flush machine connected through the transmission cooler lines to get it all. My advice would be after doing that drain and fill, drive it for a bit then do a drain and fill again. It still doesn't get 100% new fluid in there as it all mixes together but it's about as close to a flush as you'll get without a machine or some macgyver ingenuity. Hope this helps.

[idosubaru]

just check the fluid level and it's either right or wrong - adjust accordingly.

 

only get 1/3 or so of the fluid out with a drain/refill.  there's fluid up in the torque converter and valve bodies that can't drain.  it's not like engine oil.

 

the speed verses RPM is mostly mechanical gear ratio driven and wouldn't be affected by changing the fluid.  you'd have other symptoms if the fluid were low.

 

like it would be low on the dipstick.  a little bit low, even a quart, won't cause symptoms

Edited August 31, 2014 by grossgary

[Stelcom66]

Thanks for all the info - about 1/3 of the capacity seems about what was drained. A neighbor also mentioned there's the torque converter, and as mentioned other areas where the fluid will still be. I think when I brought my company vehicle to a lube shop for an oil change it was connected to a flush machine, I don't recall seeing it on a lift.

 

Nice that Subarus are so easy to change the oil, no lift needed even with his Legacy which is low compared to my Forester. My neighbor gave me a hose to fill the transmission fluid, I just ended up using a small funnel on the dipstick tube with a long funnel on top of that. In his garage there's 3 dune buggies - with Subaru 2.5 engines.

[MilesFox]

Torque converter lockup is electronically controlled. 2700 rpms is right as you will be closer to 3000 rpm past 70 mph. With electronic controlled shifting, everything you knew about trans doesn't apply with the subaru. 

 

a fluid exchange thru a machine is the most efficient way to perform a 100% flush. 

 

Thhere is nothing to gain by removing the trans pan, as you will find its just wires and solenoids and a screen, and reinstalling may risk a leak. Best to leave it be if it is not leaking. That is what the drain plug is for!

 

Stay tuned as i made video of doing a trans flush in a professional environment on a subaru, once i can load and edit the video. Good luck

[Stelcom66]

Thanks - was talking about it yesterday with some others. As you said. it's not worth trying to remove the pan, the flush machine is the way to go. A guy just did a transmission fluid change himself in his garage and flushed it - forgot what he used. Please do let us know when the video is posted. 

 

I thought by selecting 'Follow this topic' I'd get an email when posts are made to this topic, but have not so far. I'll check some other settings.

[Stelcom66]

"I thought by selecting 'Follow this topic' I'd get an email when posts are made to this topic, but have not so far. I'll check some other settings."

 

My bad - was checking an alternate email address, the forum did send a notification.

[MilesFox]

A fluid exchange machine can be simulated with a jug of fluid, a hose, and a drain pan. If you can determine the inlet and outlet hoses, you can siphon from a jug of new fluid while the engine is running, and collect the old fluid id a drain pan. This will maintain the trans initial fluid level as long as no air is introduced. It would be wise to cycle through the gears while you perform this.

 

A professional machine moves 18qts thru the trans while idling, and when connected, the internal valving will allow the fluid to move one war regardless of which lines are connected which way.