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After 1500 miles on clock I decided to take the car for a long journey, then on the way home I felt like doing a bit over 100 mph so I reached 112 mph, but after about 2 mins the AT OIL TEMP warning light came on, the safest top speed of the car as recommended by the manual is 122 mph, so how can something like that happen?what can I do to stop it? Does it really need a new pressure switch? or an CVTF change can fix it? Can it be a wear-in process that is causing all the trouble? 🙁
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I would offer that just because it is safe to go 122 MPH doesn’t mean you should do it. Production automobiles are not designed to be run continuously at the edge of their operating limits. That all being said, you can add a transmission oil cooler to the vehicle to help dissipate heat from the transmission.
You held three digit speeds on a drivetrain that wasn’t even broken in yet? Oh boy. I’d bear in mind that OEMs are getting wiser to things like this and actively looking for it. Now I can’t tell you for certain if Subaru can log abuse codes yet as they haven’t released that software to the independants yet, but if it can you’ve just voided your warranty. Volvo started doing this on their heavy duty line back around 2004 or 2005. The PCM monitors for abusive driving conditions and logs the events into the PCM. When a tech plugs into it for a driveability issue during the warranty period these abuse events are downloaded to the tech’s computer. Once abuse codes are present it is logged by the vehicle’s VIN into the OEM’s database and all powertrain warranty is voided.
Even if they don’t log abuse codes, try going to the dealer and having them look at it. When the tech views the freeze frame failure record that was recorded when this fault occurred he will not only see the temperature of the transmission but the VSS data pid reading 112mph. That alone would be enough for this and future repairs to not be covered by Subaru.
so how can something like that happen?
Traveling at excessive speed can cause the fluid to reach a very high temperature. With a vane type ATF oil pump, this is caused by the fluid being hydraulically ‘sliced’ by each vane. At high speed, the friction causes the oil to get very hot. The “torque multiplication” phase of hydraulic fluid coupling that occurs in your torque converter also causes fluid temperature to skyrocket.what can I do to stop it?
Travel at reduced speeds. This will reduce the hydraulic demands placed on the transmission oil. CVT’s are not like regular transmissions with planetary gear sets that can handle higher loads.Does it really need a new pressure switch?
Take a pressure reading of your transmission mainline pressure in different gears and see if they are in spec. If so, then you do not need to adjust mainline pressure.or an CVTF change can fix it?
Fluid change is **HIGHLY** recommended a.s.a.p. as soon as ATF oil is overheated. For example, ATF needs to be changed within 40 miles after reaching 400 degrees as opposed to ATF that stays under 200 degrees could last for 100,000 miles.Can it be a wear-in process that is causing all the trouble?
No. at 1,500 miles any break-in process is irrelevant.I drive my car very very conservatively I even managed to reach 38 MPG, but occasionally I need to drive a bit fast and it’s unbelievably frustrating let alone disappointing to own a Subaru Impreza knowing that it is incapable to handle a bit over 100 mph while others could easily reach over 120 mph without any drama, I own a Mitsubishi Lancer with a CVT also and after 90,000 miles on clock it still is capable to crack 118 mph easily, I am not North American and in my region it’s totally fine to reach speeds over 100 mph, in fact you’ll get run over if you drove this slow :cheer:
The warning light went off immediately after reducing the speed to 100 mph, I’m looking for a solution that will enable me to travel at speeds higher than 110 mph without the tranny getting hot. By asking “How can something like that happen” I meant that the Users manual said it’s ok to reach 119 mph why did it overheat at even less speed? I know what causes a Transmission to get hot, I don’t want a temporary fix I need it to be able to do the claimed top speed without any drama and by asking whether a CVTF change can fix it I meant looking for a CVTF that can withstand high temperatures produced when driving at these speeds without overheating
check with the dealer. see if you can add a oil cooler to the car (or install a larger one) without voiding warranty. they probably already use synthetic fluids but you can check to make sure. synthetics have a higher heat tolerance investigate if you can swap for a race synthetic like royal purple. see if theres any equipment off a WRX or STI that might help. weight reduction will also help. look into lighter weight aftermarket wheels and tires.
These are all things tuner friends do to their cars. so im offering what ive been told by them.
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