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Engine oil filter on transmission

After having changed the oil in my 04 Forester multiple times, I must have lost my mind and drained the transmission fluid. I realized this when I started it back up and it wouldn’t move. Clearly I put an oil filter on with engine oil around the seal. Should I do a tranny flush or can I just replace filter (with correct one) and fill with tranny fluid? Thanks!

As long as you didn’t put engine oil in the transmission, I don’t see a need for a flush. Just a little engine oil on the sealing gasket won’t hurt anything.

Do you now have 2X the oil in the engine? You’ll need to fix that.

Am I missing something???

I have no idea what you did with the oil filter…it WON’T fit a transmission filter. And you don’t have an external tranny filter. This makes no sense.

Mike, Subarus have an external spin on transmission filter:

Haha. That’s good. You think this guy is yanking your chain?

There is no need to flush the transmission. Get 5 quarts of the correct fluid and pour 3 into the transmission. Then, start the engine and shift to 1, then up through each gear and back to park. With the engine still running pull the dipstick, wipe it clean and check the fluid level. Be patient as it often requires repeated wiping and re-sticking due to fluid on the tube walls. Add fluid if needed to bring the level up to near the ADD level. Specifically, that means DO NOT ADD FLUID UNTIL YOU REACH THE FULL MARK. If you fill it cold it will be overfilled when hot and overfilling is a much greater problem than underfilling.

You need to realize that the fluid level can only be determined when the engine is running at normal operating temperature. But you must first get it up to a minimum operating level and run it until it is hot and then add fluid incrementally to about midway of the full range.

There is probably only about 1 tablespoon of engine oil on the filter. And yes, the tranny filter and engine filter are the same size. This is my wife’s car and she took it to a quick change the last couple of times so I didn’t even think about it when I crawled under there.

Can I now use the engine oil filter in the correct location or should I just ditch it since it has transmission fluid in it? And what about the extra 5 qts of engine oil? I know I need to drain all of that but now I have 5 new qts of synthetic oil mixed in with dirty oil. Should I just dump it all and start over completely?

I already told my wife she cannot breath a word of this to anyone we know…how embarrassing!!

Dump the oil, replace the filter and start over.

And don’t be too embarassed. I have pulled the wrong plug on vehicles and I’m supposed to be an expert.

Figured as much! Thanks guys. She told me this morning she hasn’t replaced the tranny fluid since she’s had the car (a lot of miles) so I guess things happen for a reason!!!

Any recommended transmission fluid? Should I suck it up and go to Subaru?

Sadly, I’d recommend you dump all the oil you drain. There is no way to keep the new synthetic from mixing with the old oil. You can’t use the filter either if it has transmission fluid in it. For the motor you have to do a complete oil change with new oil and a new filter.

As for the transmission, a bit of oil on the rubber seal shouldn’t be enough to contaminate the transmission fluid. At this point I don’t see a reason not to change the transmission fluid as well. I wouldn’t flush it, just drain and replace. If the transmission filter is $5.00 or so I’d spring for a new filter too.

In the end you just want to feel good that you have fluids with no cross contamination issues.

I’d go with Subaru transmission fluid, I’d want to make sure nothing affects it.

UncleTurbo, why should the OP throw away a good filter? He/she said he/she had drained the tranny.

Just change the filter, fill with fluid, and don’t worry about a thing.

Do not be embarassed over this. Even pro mechanics make mistakes that lead to those WTH was I thinking moments.

read the owners manuel or yes visit the dealers parts dept…

Got about another qt of tranny fluid out when I pulled the oil filter (makes about 5 total including original draining). Drained motor oil, replaced filter and filled with new oil. Added 3 qts Dex III to tube with dipstick labeled ATF. Followed instructions of moving through gears then added another qt after measuring. After multiple sticks, it still only shows level at cold full. Should I continue to add until it’s closer to hot low measure?

Like Knox says, start over and get everything the way it belongs…