No can read tranny fluid

subaru
legacy
fluids

#1

I cannot get an accurate reading of the automatic transmission fluid level on my 95 subaru legacy L (fwd). I never have been able to.



I bought it with 95K, now it has 230K, and I’ve never had trouble with the transmission. In fact, I’ve never had a car that lived this long with it’s original transmission. It’s had other problems, but that’s beside the point. The dealer told me that the transmission fluid was changed when I bought the car.



How can I get an accurate reading? The fluid level is all over the place on the dip stick. I follow the recommended procedures for reading it - hot, in park, engine running.



Otherwise, the fluid looks to be in good condition - just slightly darker than it was 100K miles ago. But the car is old, I’d like to change the fluid.



Any advise on how I can determine the proper level when I refill it? Measure what comes out and replace the same amount, perhaps? Is there an accurate method of reading the level?


#2

Level will vary depending on the temperature of the fluid. A manual will tell you volume for a due fluid change.


#3

Just for experimental purposes check it cold with engine off


#4

“I follow the recommended procedures for reading it - hot, in park, engine running.”


#5

It will read much too high. All the fluid that should be in the torque converter is in the oil pan.

The proper recommended method: “Hot, in park, engine running, on level surface”. Last part is just as important. Also, 100K miles on the trans fluid is much too long. I typically use 35K and never exceed 60K.


#6

Thanks for the tips. It seems to me that the curved design of the dipstick tube is a great hinderance to getting an accurate reading. This makes what should be a simple procedure a bunch of guesswork. The manual says four quarts for a “standard” change. I think what I’ll do is change it a couple of weekends in a row, replacing about the same amount that I catch in the drain pan each time, so the level will remain in the ball park and eventually I will change most of the fluid.


#7

Are you checking it on LEVEL ground ?


#8

If your transmission is not misbehaving and you’re just asking about how to keep it at its current level during a change, then yes - just measure what comes out and add the same amount. I would trust this way before trusting what the manual says.

Regardless of vehicle, I too have always found getting a good read on the trans fluid much harder than say engine oil. The “check while hot” only partly helps because “hot” isn’t just one thing. There’s a lot of variation and different temps do change the level. Hot fluid is also thin and runny and, if clean, translucent. I always check when running and cold if ambient temps are fairly warm, and then I check again after a really long drive when I figure it is at it full temp.


#9

What he said


#10

It usually requires repeated wipe and re-sticks to get the correct level indicated. The stick wipes fluid off the tube as it is pulled out.


#11

Would it make sense to drain the transmission completely and then put in the amount specified in the manual? Or is this really the one instance where you throw the manual out the window?


#12

There usually isn’t a way to drain all of the transmission fluid. The manual will be about right so there’s no need to throw it out the window entirely. Its just that the manual can only tell you “in principle” what its supposed to be. But on the ground out in the garage there is what actually came out as part of the draining. In the end, you have to use the dipstick as the final say so anyway.