ATF was low - whistling while accelerating

[tpattgeek]

This is loosely related to a previous post in the Maintenance section about an unknown whistling coming from my 07 Civic. That post can be found here:

https://bobistheoilguy.com/forums/threads/whistling-while-accelerating.199949/

After a week or so, I finally thought about checking the fluid while the engine was hot and on level ground (when I got to work). The whistling was only happening while accelerating at slow-medium speed and was not noticeable (or very faint at least) in P or N. I checked the fluid the first couple minutes after turning the car off, like the manual says to do, and it was directly on the LOW line. The stick has a MAX line and a lower line, possibly not labeled, and it was in fact low. I had about a half quart in the trunk so I poured some in for a few seconds then checked it. It barely moved off the lower line, so I had to end up putting in about a half of a quart, maybe more.

I guess my questions/concerns are:

I just changed the AFT 6 months/5k miles ago and I never see leaking under it, so what other reasons are there for it to be low? When I changed it 6 months ago, I probably added the new fluid while the engine was almost completely cold. Would that have that much of an effect on the level? I know I added the new fluid to the MAX line, so I'm guessing it just "filled in the gaps" from the change. Does that sound reasonable?

Also, what is the likelihood that anything was damaged? IF this solves my whistling problem, what else should I look for? Other normal AT issues? Slipping, hesitating, clunking into gears, etc.? Should I go ahead and do another change in case there is higher than usual metal shavings in there now? I know I'm probably overreacting, but that's why I'm here. Thanks!

 

[JHZR2]

Are you totally sure it was really full aftter your ATF change? Filter media can take some time and some fluid to fully wet.

 

[tpattgeek]

Originally Posted By: JHZR2
Are you totally sure it was really full aftter your ATF change? Filter media can take some time and some fluid to fully wet.


Yes, I did it all myself and would never drive it if it wasn't directly on the max line.

Also, it isn't labeled MAX, it is actually labeled HOT on the upper line, and nothing on the lower line, I believe.

 

[Hermann]

Was it drained and filled on level ground. You mentioned you had to wait till you got to work for level ground.

 

[tpattgeek]

Originally Posted By: Hermann
Was it drained and filled on level ground. You mentioned you had to wait till you got to work for level ground.


Yes, I work on it under the carport when it's time for maintenance, but I park on the driveway's incline everyday. My oil is a full quart low if I check it on the incline.

Freaked me out the first time. Checked it at work the next day, at the full mark.

 

[Hokiefyd]

You likely did zero damage with it on the lower line. I fill mine to have it near the max line, but not necessarily ON the max line.

Because draining/refilling a Honda AT is so easy, and there's no external filter to change, I simply measure the fluid I get out and put exactly that much back in. Even if it shows high or low directly after the fill (before I drive it), I know that after I drive it for the first time, it will be exactly where it was before I began. Of course, I do check it periodically, but the level never changes on our two.

 

[440Magnum]

Originally Posted By: tpattgeek
Originally Posted By: JHZR2
Are you totally sure it was really full aftter your ATF change? Filter media can take some time and some fluid to fully wet.


Yes, I did it all myself and would never drive it if it wasn't directly on the max line.

Also, it isn't labeled MAX, it is actually labeled HOT on the upper line, and nothing on the lower line, I believe.


Did you re-check after a few hundred miles of driving? It can take a loooong time to fully purge all the air out of some AT's

Other than that, keep a watchful eye on the in-radiator heat exchanger. Its not uncommon for them to lose ATF into the coolant (and vice-versa after engine shutdown) which makes a mess of both systems.

 

[MolaKule]

Originally Posted By: JHZR2
Are you totally sure it was really full aftter your ATF change? Filter media can take some time and some fluid to fully wet.


for sure.

I recently replaced the fluid in my '08 Trailblazer and carefully removed the filter and just for kicks, measured the amount of fluid remaining in the filter housing.

The filter held 270 mL or about 9 ounces of ATF, so one has to make up for that.

I measure my ATF levels on level ground in the garage while engine is running and cycling it through the gears.

Since I cannot get it up to max temp while in the garage, I set the level to halfway between cold and hot.

After a "spirited" drive, I recheck it when back in the garage and the level will show the fluid up to the "Hot" mark.

This procedure has worked well for all my vehicles.