DIY Tranny Flush/Complete Drain. Opinions/Info?

[88coupe]

93 Legacy - New timing belt & water pump, Tune-up, Intake system cleaned, new filters etc. The car runs much better but still seems auto trans is sluggish. No real hard shifting or slipping but lacking umpf.

 

I would like to change the fluid and filter screen & dont want to have a shop do it- prices are high, employee's are inexperienced, parts and performance lack workmanship & quality. I want to Drain the whole system not necessarily flush it, just get out all the old fluid out & replaced.  I have searched on "how to do it yourself" & have a general idea of what to do.

 

Take one of the trans cooler lines off to pump out the old fluid that isnt in the pan, Drain & remove pan then clean it out & remove old gasket material/residue, replace filter/screen gasket & trans pan, And refill with ATF.

More or less this is the "How to" I found but very simplified. I think pumping/draining out of the cooler line would be done before the pan right? Would new fluid need to be added while pumping out so system doesnt run dry? I'd rather not run a bunch of new fluid in it just to throw it away.

 

I would like to know if anyone has done a flush or drain the whole system at home & what procedure(with details) was used, problems or issues occurred, *lack of a better term* "Tricks"/techniques to use.

 

What brand ATF is most commonly used by members? Any bad experiences with NAPA brand/Or similar ATF?

 

What is a good way to clean trans out before adding new ATF? I was thinking about adding SeaFoam Trans Tune to help clean it out. Anyone used SeaFoam Trans Tune (not regular seafoam) before? Also read that Trans-X has been used & recommended by quite a few subaru owners in their auto's to help or prevent issues. Add SeaFoam Trans Tune drive a few miles, drain & replace with new fluid and Trans-X additive, what do you think?

 

Any & All helpful information or ideas and opinions are appreciated, hope to get replies/responses ASAP, Thanks.

 

 

 

 

[lmdew]

Don't bother dropping the pan.  There is NO filter in there, just a pickup screen that I've never seen dirty or plugged.  

I use the Drain, Fill, Pull the Trans cooler hose and pump out the old fluid.   

Do this about 3/4 of a gallon at a time, refilling the trans each time.

 

In about 3 gallons the fluid will be coming out nice and clean.

 

Your year Subaru, Subaru does offer an external filter kit.  If it has this the filter is up in the engine compartment on the drivers side frame rail.  Add it if you like.

 

Super Tech, Wally World is what I use.  Cheap and good quality, at least I've never had any issues.  I'd rather buy cheaper fluid and change it sooner that buy expensive stuff and leave it in there for 100K.

[Rooster2]

Don't bother dropping the pan.  There is NO filter in there, just a pickup screen that I've never seen dirty or plugged.  

I use the Drain, Fill, Pull the Trans cooler hose and pump out the old fluid.   

Do this about 3/4 of a gallon at a time, refilling the trans each time.

 

In about 3 gallons the fluid will be coming out nice and clean.

 

Your year Subaru, Subaru does offer an external filter kit.  If it has this the filter is up in the engine compartment on the drivers side frame rail.  Add it if you like.

 

Super Tech, Wally World is what I use.  Cheap and good quality, at least I've never had any issues.  I'd rather buy cheaper fluid and change it sooner that buy expensive stuff and leave it in there for 100K.

I fully agree with what Imdew's response above. Don't bother dropping the pan, as stated there is only a screen in there. I made the mistake of dropping the pan on a 91 Leggie years back, found the screen clean, then had a hell of a time sealing the pan cover back on. Removing the old gasket material is a nasty job, as it is very difficult to remove. It forever slightly leaked afterwards, even with a new gasket.

 

I too, have had good luck with Walmart's Super Tech brand of ATF. I have been using it for years with no issues.

 

I have done the drain and fill three times approach to changing ATF, with short drives between changes. Seems to produce clean fluid afterwards.

 

I hope a fluid change improves your tranny performance. Keep us posted.

[upnorthguy]

I just did this on my 95 a few weeks ago.  I just put it on ramps and drained/filled three times as Rooster described.  Getting at the drain plug is easier/quicker for me than fiddling with the AT cooler hose connection in the tight quarters.  I used the house brand ATF from Advance Auto and it is working fine.  By the third drain the fluid was looking good.

 

The hardest part was getting the funnel into the ATF fill tube (and that wasn't too bad).  Make sure you have a long neck funnel.

[88coupe]

So this "Automatic Transmission Filter" is what some call a "pickup screen"?

 

http://contentinfo.autozone.com/znetcs/product-info/en/US/chl/TF222/image/4/

 

They dont really get dirty so they dont need replaced? All of the ATF goes threw that screen right? So the majority believe the Auto Trans Filter/Pickup Screen is not worth replacing?

 

So a '93 Legacy Auto Trans (4EAT) doesn't have any other filters besides "Pickup Screen" & the external option from Subaru? I have read that adding a extra filter to a 4EAT is a good option to help operation & longevity. Would a in-line filter be usable or would it restrict flow too much? What about adding extra magnets inside the pan? How do you all feel about using additives in the tranny, Any specific brand that you stand by? Because wanted to use a cleaner before the fluid change & a additive with the new ATF.

 

Inline Auto Trans Filters

http://s7d9.scene7.com/is/image/GenuinePartsCompany/NWMDC?$Product=GenuinePartsCompany/1471439

 

Can a Inline Power Steering Filter be used as a Inline Auto Transmission Filter?

They look similar but they flow rate might be different.

http://www.rockauto.com/getimage/getimage.php?imagekey=2322336&imageurl=http%3A//my.cardone.com/Imagesftp/20/200038F-01.jpg

[Rooster2]

So this "Automatic Transmission Filter" is what some call a "pickup screen"?

 

http://contentinfo.autozone.com/znetcs/product-info/en/US/chl/TF222/image/4/

 

They dont really get dirty so they dont need replaced? All of the ATF goes threw that screen right? So the majority believe the Auto Trans Filter/Pickup Screen is not worth replacing?

 

So a '93 Legacy Auto Trans (4EAT) doesn't have any other filters besides "Pickup Screen" & the external option from Subaru? I have read that adding a extra filter to a 4EAT is a good option to help operation & longevity. Would a in-line filter be usable or would it restrict flow too much? What about adding extra magnets inside the pan? How do you all feel about using additives in the tranny, Any specific brand that you stand by? Because wanted to use a cleaner before the fluid change & a additive with the new ATF.

 

Inline Auto Trans Filters

http://s7d9.scene7.com/is/image/GenuinePartsCompany/NWMDC?$Product=GenuinePartsCompany/1471439

 

Can a Inline Power Steering Filter be used as a Inline Auto Transmission Filter?

They look similar but they flow rate might be different.

http://www.rockauto.com/getimage/getimage.php?imagekey=2322336&imageurl=http%3A//my.cardone.com/Imagesftp/20/200038F-01.jpg

IMO, adding any extra tranny filter is not worth the effort, unless you plan on pulling a trailer over hills and mountains. Under normal driving, the 4EAT tranny does not over heat and require anything special. I don't recommend any additives, ordinary ATF is all you need.

[Fairtax4me]

Use Dexron III fluid, or any fluid that meets that spec.

Like Lmdew said, wal-mart super tech is the same stuff you get in the auto part store house brand, just at a cheaper price.

 

Changing the screen filter is a waste of time.

Dropping the pan will only lead to a leaking pan.

 

I do the drain and re-fill 3x method. Take short drives in between to cycle new fluid through the trans.

[presslab]

The transmission computer controls the shift points, this is the only thing that I could see affecting the "umpf" of the transmission.  Is it holding onto gears too long?  In any case I'd recommend checking the TPS adjustment as this tells the transmission when to change gears.  Maybe the engine is just down on power.

 

I have seen severely blocked filter screens in the transmission.  But I doubt this is your problem.

[88coupe]

Well the thing Im worried about is the car has over 310k mi and is drivin 250mi + every week round trip out of town and back commute. The engine has been replaced (with a EJ20) but I dont have much past info of the tranny so I want to take preventive maintenance precautions to ensure vehicle operation. This is my fathers car and I want to be sure of its reliability & safety. Is it harmful to use a cleaner/flush additive before fluid change?Also the reason to replace filter because it could get filled with deposits and/or debris after using additive.

 

Are the 4EAT filter screens made of actual metal mesh screen material or is it some kind of paper media?

 

What is the majority feeling of adding extra magnets to the pan?

[presslab]

The filter screen is a single flat plastic mesh.

 

There is little reason to add another magnet to the pan.  The wear of gears and steel is very minimal, most of the wear is from the friction material.

[88coupe]

So the addition of a Inline Filter is not such a bad idea considering material can contaminate the ATF & also  the 4EAT was fitted with more filters later in the production. Maybe its overkill but my understanding of 4EAT's is they're prone to malfunction & operation failure, more so than most automatics. Im not hating on 'em but its all info I got off USMB or similar sites. There is a lot of "conflicting ideas & opinions" from forum members, so its difficult sometimes to cipher through and draw a solid conclusion from threads & posts when each "answer or educated estimate" conflicts with another.

 

How many quarts does a 4EAT take? And how many needed for a solid flush?

[88coupe]

Is the TPS adjustable, from the small screw holding it in place there looks to be a small margin of movement?

[Junkie]

Everything I've heard is that the 4EAT is pretty bulletproof unless you're making big power. I very rarely hear of any issues with them. If you want it to last longer you could add another cooler. 

[88coupe]

Additional cooler is not a bad idea, they're pretty cheap overall & could install without a whole lotta work. What stage cooler would be recommended: Light, Medium, Heavy Duty?

 

So adding a inline filter is near pointless for the older 4EAT's? I kinda thought that if the newer models had additional filters added to their design that the 4EAT needed extra filtration to ensure prolonged operation. What is the "average" life span of a 4EAT with proper maintenance & up keep?

 

HEY! This is a little off topic but can a Crankshaft Sensor from a 2nd gen Legacy be "engineered" to plug in to the stock connector of a 1st gen Legacy? The reason I ask is they look identical but the 2nd gen is 1/8 of the price of a 1st gen sensor, About $25 compared to $200! Also can it be done with the Camshaft Sensor? And would a Vehicle Speed Sensor from a junk yard be worthless or is it worth a shot? Car has been without Speedo function since purchase, CEL indicates VSS.

Edited April 28, 2014 by 88coupe

[Fairtax4me]

Is the TPS adjustable, from the small screw holding it in place there looks to be a small margin of movement?

TPS is adjustable, but should not be messed with unless you have a code for it or have checked the voltage output and found it to be out of spec.

 

Go to a u-pull junkyard and grab cam/crank sensors. They all work the same and rarely fail. If you want got try retro-fitting between generations cut the connectors off the harness and wire them up. Only two wires, and they should be the same color codes.

 

The VSS in your 93 is in the speedometer. Your speedometer is cable driven. More than likely the cable is broken, though sometimes the drive gears in the trans strip.

Edited April 29, 2014 by Fairtax4me

[88coupe]

TPS is adjustable, but should not be messed with unless you have a code for it or have checked the voltage output and found it to be out of spec.

 

Go to a u-pull junkyard and grab cam/crank sensors. They all work the same and rarely fail. If you want got try retro-fitting between generations cut the connectors off the harness and wire them up. Only two wires, and they should be the same color codes.

 

The VSS in your 93 is in the speedometer. Your speedometer is cable driven. More than likely the cable is broken, though sometimes the drive gears in the trans strip.

 

The Chilton's book shows it having a VSS 1 & 2. #2 is located at the end of the tranny and sends a signal to the #1 sensor, is what it shows. But there is only one in the 1st gen Legacy's? Do you know where its located?