Proper procedure for CVT Fluid Change on FA20DIT equiped with CVT or 15+ WRX with automatic transmission (CVT) and 14-18 Forester xt (CVT).
14-18 Forester XT CVT Automatic Transmission, Fluid Change Procedure
Advice for all reading this, do this at a licensed mechanic shop, it does not have to be done by the Subaru dealer, no matter what any body on this forum says or what the dealer says. Everyone should read their warranty. Even though Subaru service and sales departments are saying that the fluid is good for the life of the transmission they are doing nothing but blowing smoke up everyones butt. Please read your owners manuals (Warranty and Maintenance Booklet page 31 Note "#4 under severe driving replace the CVT oil should be replaced under severe driving at 24,855 miles") it says transmission fluid service should be done at roughly 25k (24,855 miles after severe service) if vehicle is towing or has severe service. Rather vague on severe service.
Here is Subaru's definition of severe driving: Quoted from https://www.worldsubaru.com/subaru-maintenance-schedule.htm
"*Examples of Severe Driving Conditions:
•Repeated short distance driving.
•Driving on rough and/or muddy roads.
•Driving in dusty conditions.
•Driving in extremely cold weather.
•Driving in areas where road salts or other corrosive materials are used.
•Living in coastal areas.
•Repeated trailer towing."
To the point, fluid service is mentioned in the owners manual and the factory designed into the transmission a drain plug, a fill plug and created a fill and fluid level adjustment procedure. All that for something that was never to be serviced sound unbelievable.
So back on topic.
Do this with or at a licensed mechanic shop and get a receipt, this will CYA. Subaru extended warranty will accept work done by licensed mechanics, yes I know we can change our own oil and our warranty is not voided as long as we have receipts. This job is a little more complicated and I think the extra cost is worth not have the debate with Subaru of America if the transmission fails down the road. That could happen if you do or don’t touch the tranny.
To satisfy all the fear mongers about taking it to the dealer, I will say this YOUR ABSOLUTLY CORRECT. If anyone can afford and they trust their particular dealer then preferably do this at the dealer. Tell them you want a cvt fluid drain and fill. Mention all the argument up top and don't let them talk you out of it. Most dealers will try very hard to talk you out of it. It occured to me. I changed my mind after reading the maintenance book and also talking in back allys with subaru mechanics and studying and coming to understand how a cvt operates.
Parts list:
31728AA121 (transmission pan filter)
SOA748V0200 (5gal bucket of Subaru High Torque CVT Fluid)
803916010 (transmission drain plug crush washer)
803918060 (transmission fill plug gasket)
Permatex The Right Stuff
Labor Time for Professional 2HR
Must be done with the vehicle completly level!
1) Drain fluid, inspect for color and oder.
2) Remove fill plug at rear end of transmission case (allen plug)
3) Drop pan replace pan screen, clean magnet, clean pan well, remove all original subaru orange Gasket Maker (rtv). Clean pan with brake cleaner remove all metal particles and rtv debris. You should be able to eat on that pan. Use rags that won’t leave many fibers behind. That pan should have nothing not even dust in it when done. Just the nice clean magnet.
4) Clean off all original subaru orange gasket maker (rtv) material from mating surface on CVT. Wipe clean with brake cleaner. No brake cleaner in valve body or CVT. Just use it on a rag to remove oil and depris from mating surface.
5) Clean mating surface of transmission pan with rotary cleaning wheel, when done it should be clean shiny metal for the mating surface of the pan. Wipe clean with brake cleaner.
6) Apply Permatex " the right stuff " to the transmission pan, use this and read directions. Simply put it cures fast and the equipment can be returned to service immediately.
7) With a friend holding the pan up mate it to the bottom of the transmission. Before mating wipe clean any oil drips from mating surface of transmission case. Finger tighten screws, first do the corners.
8) Install remaining screws hand tight. Then lightly torque in cris cross pattern.
9) Lightly torque is super important. This is a steel screw going into aluminum. If you don’t understand lightly tight don’t do this. Sorry I don’t have torque specs for you.
10) Replace transmission pan drain plug, use new crush washer. This is the same crush washer used when changing the motor oil (same part #803916010). Torque to lightly tight.
11) Fill transmission through fill plug in rear of transmission. Fill with High Torque cvt fluid using a new pump. Do not contaminate cvt and cvt fluid with any foreign material or fluid.
12) Fill till fluid drips out fill port. Reinstall drain plug with original gasket lightly tighten.
13) Start engine and idle till transmission fluid temp comes to between 95f-113f. I found many service managers recommending 105f. Don’t use a thermometer or thermal gun. Use a vehicle diagnostic computer that can access transmission temp out of the TCU.
14) Run gear selector through the gears. R N D then D N R P. This ensures fluid is well circulated.
15) With engine running and transmission in park remove fill plug. Add cvt fluid to transmission till is drips out the fill plug. When it’s at a slow drip to no drip reinstall fill plug. Remove old gasket and use new gasket (part #803918060). Torque to light tight, torque spec 35 ft/lbs.
16) Clean everything up, clean off any splashed cvt fluid on transmission and exhaust.
17) Check for leaks and weeps. Tighten transmission pan drain plug if its leaking or weeping till leak/weep stops.
18) Now your going to need an advanced diagnostic computer. Most of us will have to go to a professional shop that has access to putting the transmission TCU through a relearn procedure. I’m not going to post what it is because all of you need to go to a proper professional mechanic for this. The procedure does only take 20 mins though and will have to be done with the transmission fluid temp around that 105f point mentioned earlier. If you had followed my advice and done this with a professional mechanic who can access this in the TCU then you done.
19) Tip your mechanic and have a beer. Drive lightly no WOT or quick acceleration for 50 miles let the transmission figure its self out with the new fluid.
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14-18 Forester XT CVT Automatic Transmission, Fluid Change Procedure
Advice for all reading this, do this at a licensed mechanic shop, it does not have to be done by the Subaru dealer, no matter what any body on this forum says or what the dealer says. Everyone should read their warranty. Even though Subaru service and sales departments are saying that the fluid is good for the life of the transmission they are doing nothing but blowing smoke up everyones butt. Please read your owners manuals (Warranty and Maintenance Booklet page 31 Note "#4 under severe driving replace the CVT oil should be replaced under severe driving at 24,855 miles") it says transmission fluid service should be done at roughly 25k (24,855 miles after severe service) if vehicle is towing or has severe service. Rather vague on severe service.
Here is Subaru's definition of severe driving: Quoted from https://www.worldsubaru.com/subaru-maintenance-schedule.htm
"*Examples of Severe Driving Conditions:
•Repeated short distance driving.
•Driving on rough and/or muddy roads.
•Driving in dusty conditions.
•Driving in extremely cold weather.
•Driving in areas where road salts or other corrosive materials are used.
•Living in coastal areas.
•Repeated trailer towing."
To the point, fluid service is mentioned in the owners manual and the factory designed into the transmission a drain plug, a fill plug and created a fill and fluid level adjustment procedure. All that for something that was never to be serviced sound unbelievable.
So back on topic.
Do this with or at a licensed mechanic shop and get a receipt, this will CYA. Subaru extended warranty will accept work done by licensed mechanics, yes I know we can change our own oil and our warranty is not voided as long as we have receipts. This job is a little more complicated and I think the extra cost is worth not have the debate with Subaru of America if the transmission fails down the road. That could happen if you do or don’t touch the tranny.
To satisfy all the fear mongers about taking it to the dealer, I will say this YOUR ABSOLUTLY CORRECT. If anyone can afford and they trust their particular dealer then preferably do this at the dealer. Tell them you want a cvt fluid drain and fill. Mention all the argument up top and don't let them talk you out of it. Most dealers will try very hard to talk you out of it. It occured to me. I changed my mind after reading the maintenance book and also talking in back allys with subaru mechanics and studying and coming to understand how a cvt operates.
Parts list:
31728AA121 (transmission pan filter)
SOA748V0200 (5gal bucket of Subaru High Torque CVT Fluid)
803916010 (transmission drain plug crush washer)
803918060 (transmission fill plug gasket)
Permatex The Right Stuff
Labor Time for Professional 2HR
Must be done with the vehicle completly level!
1) Drain fluid, inspect for color and oder.
2) Remove fill plug at rear end of transmission case (allen plug)
3) Drop pan replace pan screen, clean magnet, clean pan well, remove all original subaru orange Gasket Maker (rtv). Clean pan with brake cleaner remove all metal particles and rtv debris. You should be able to eat on that pan. Use rags that won’t leave many fibers behind. That pan should have nothing not even dust in it when done. Just the nice clean magnet.
4) Clean off all original subaru orange gasket maker (rtv) material from mating surface on CVT. Wipe clean with brake cleaner. No brake cleaner in valve body or CVT. Just use it on a rag to remove oil and depris from mating surface.
5) Clean mating surface of transmission pan with rotary cleaning wheel, when done it should be clean shiny metal for the mating surface of the pan. Wipe clean with brake cleaner.
6) Apply Permatex " the right stuff " to the transmission pan, use this and read directions. Simply put it cures fast and the equipment can be returned to service immediately.
7) With a friend holding the pan up mate it to the bottom of the transmission. Before mating wipe clean any oil drips from mating surface of transmission case. Finger tighten screws, first do the corners.
8) Install remaining screws hand tight. Then lightly torque in cris cross pattern.
9) Lightly torque is super important. This is a steel screw going into aluminum. If you don’t understand lightly tight don’t do this. Sorry I don’t have torque specs for you.
10) Replace transmission pan drain plug, use new crush washer. This is the same crush washer used when changing the motor oil (same part #803916010). Torque to lightly tight.
11) Fill transmission through fill plug in rear of transmission. Fill with High Torque cvt fluid using a new pump. Do not contaminate cvt and cvt fluid with any foreign material or fluid.
12) Fill till fluid drips out fill port. Reinstall drain plug with original gasket lightly tighten.
13) Start engine and idle till transmission fluid temp comes to between 95f-113f. I found many service managers recommending 105f. Don’t use a thermometer or thermal gun. Use a vehicle diagnostic computer that can access transmission temp out of the TCU.
14) Run gear selector through the gears. R N D then D N R P. This ensures fluid is well circulated.
15) With engine running and transmission in park remove fill plug. Add cvt fluid to transmission till is drips out the fill plug. When it’s at a slow drip to no drip reinstall fill plug. Remove old gasket and use new gasket (part #803918060). Torque to light tight, torque spec 35 ft/lbs.
16) Clean everything up, clean off any splashed cvt fluid on transmission and exhaust.
17) Check for leaks and weeps. Tighten transmission pan drain plug if its leaking or weeping till leak/weep stops.
18) Now your going to need an advanced diagnostic computer. Most of us will have to go to a professional shop that has access to putting the transmission TCU through a relearn procedure. I’m not going to post what it is because all of you need to go to a proper professional mechanic for this. The procedure does only take 20 mins though and will have to be done with the transmission fluid temp around that 105f point mentioned earlier. If you had followed my advice and done this with a professional mechanic who can access this in the TCU then you done.
19) Tip your mechanic and have a beer. Drive lightly no WOT or quick acceleration for 50 miles let the transmission figure its self out with the new fluid.
