Checking Transmission fluid

#1

Why do i have a variation in fluid level when i check the trans. cold in my 2007 Honda Accord V6

When i check the fluid 2-3 times a week it reads full,or at the add mark.

The manual says to check it after warming it up awhile,but i have always been in the habit of checking fluids when engine has set for several hours in my American vehicles.

Why is the level never the same?

#2

ATF expands when hot,your checking your ATF 2-3 times a week?

Why do you not want to perform the check as the manual states?

#3

I checked the fluid level cold to see if there was a point on the dipstick i could use for a reference when cold. I don’t question condition of the tranny,just want to understand why the level changes like so.

#4

Follow the procedure recommended in the manual It is recommended because it provides the most accurate and consistent results.

#5

Personally, I always overfill my transmissions by a bit; usually 1/2 to a full quart.
The reason for this is that on some models hard acceleration or cornering can cause the fluid to slosh away from the filter pickup since the pans have no baffle plates and this can cause a momentary loss of fluid pressure or an air pocket.
The extra fluid compensates for that and hurts nothing.

The slosh effect occurs in the gas tank also but fuel tanks have baffles built in to prevent fuel from sloshing instantly away from the fuel pump and causing engine hiccups.

#6

Thanks for the inputs

#7

are you kidding me, most transmission pans arent deep enough for baffles or to create the problem you mention. and personally if i had to choose to be a little(and i do mean a little) low on transmission fluid or overfilled i would choose to be a little low due to areation concerns and the lack of lubrication that would result from this.and as oldschool ask why are you checking transmission fluid 2-3 times a week?

#8

No I’m not kidding you. Being a quart over will not cause an aeration problem but being a quart down will certainly cause a problem.
After doing this for 30 years or so I’m still waiting for the first case of aeration.

Other than these, do some reading up on this problem.
http://www.southernhighrollers.com/tech/articles/trannypan.html

Here’s part of a bulletin in regards to Ford police cars.
The factory installed transmission pan was also revised to contain a deep well to prevent fluid starvation during hard turns and other evasive maneuvers where fluid slosh is a concern.

Consider that with some transmission filters the intake is on the top side of the filter and the problem becomes even worse.

Sorry, but fluid slosh is not a rare thing to occur and baffles could certainly be fitted into a shallow pan. The auto makers won’t do it because it would add 4 cents to the cost of production.

Wonder how many people experience a hiccup in their car while accelerating or cornering due to a momentary fluid loss and both they and the mechanics go nuts trying to figure out why the engine is cutting out?

#9

Grampy,
DON’T overfill your transmission. It would be safest to fill it to the top of the hatch mark, when warm, with the engine OFF. On Honda, you WON’T find instruction to check the transmission with the engine running; so, don’t.
The Ford Crown Victoria has a drain and refill volume, including the torque converter, of 13.6 quarts. Not counting the torque converter, a refill would be less.
The Honda V6 automatic transmission has a refill volume of 7.4 quarts, including the torque converter. Not including the torque converter, it’s less, of course.
An over-fill by the same amount in the smaller volume transmission (the Honda) of, say a quart, would be equivalent to two quarts of overfill in the Crown Victoria’s automatic transmission.
So, if you must rock-crawl, or perform high-speed turns with your Honda, be careful with the overfill.

#10

My daughter runs her Mitsubishis (FWD) overfull and at 7 years and counting of Mitsu ownership (3 of them) has not experienced any aeration of the fluid.

#11

Oy, there’s a reason I go with a manual whenever it is available. Fluid? Maybe if I feel like it at 100K miles :slight_smile:

#12

I’m going to check the level according to the recommended way in the manual.
When i get several get several readings this way over the next several days. I’ll post back.

#13

im not gonna argue with you i stand by what i said and if u have been doing this for 30 years and never seen aeration u aint looking close enuf.

#14

Oh, There’s A Reason I Go With An Automatic Whenever It Is Available

I don’t have to shift all the time and spill my coffee. One of my six cars has a manual transmission and it doesn’t have adequate (any) cup holders.

You’d be surprised at how comfortable it is to drive an automatic, even if you think you’re a purest. I can speak from a few decades of manual trans experience.
I used to try and read maps while I drive, too. Now some lady in my GPS directs me. I get to concentrate on driving.

I left the manuals behind when lock-up convertors became standard.

America, What A Country.

#15

Update:
Checked the fluid level the last couple of days AFTER the car was warmed up,shifted through gears,and the level was where it was supposed to be,and repeatable.

Why the level was COLD varied from day to day is something else,and NOT the way to do the fluid check.

Thanks to all who commented