Checking transmission fluid - why do some techs and publishers say keep car running

[Aarmin]

So I have in front of me my 2005 owners manual and a Haynes manual (2005 copyright). The owners manual says check the transmission fluid with the engine off, but the Haynes manual says check it while idling.

Why does Haynes recommend this? Or could it be another case of technical issues, Haynes isn't always on target but they do put a lot of effort into their publications.

Regardless, I know the procedure Honda calls for so please don't reply with what Honda says, that's not what I'm asking.

[imanewb]

I'm very interested to in this subject. I usually check it within 90 seconds while the engine is off. I've read on a few websites and seen a youtube video where they say to check it while idling.

[MikeCz]

Because of design differences between transmissions. Some transmissions may have high torque convertor drain back; checking with the motor running will keep the convertor full. Hondas recommendation for checking within 90 seconds (motor NOT running) is most likely to overcome the chance of any “slow” drain back. Some of us have noticed no difference between Hot or Cold levels nor have any Convertor drain back, other notice a difference.

1. The Haynes manual is wrong.

2. Other Haynes Manuals I have are also wrong with things like torque settings and sequence.

I now trust only the HONDA Workshop manuals.


ADDED: It’s important to remember that the dip stick calibration marks on the Honda are designed to be correct only when the Engine is at operating temp and the Motor is not running. Checking with Motor running will result in oil circulating throughout the transmission which “could” lower the reading on the dip stick, resulting in an overfilled transmission if that reading was been used to top up the fluid level .

[BLCKFLSH]

Get the engine at running temperature, shut it off, then check the level between 60 and 90 seconds. Haynes has it wrong. Honda automatics have always been checked with the engine off. Personally, I've found the level is pretty much the same, with the engine hot or cold, but I do it Honda's way.

[Aarmin]

Originally Posted by BLCKFLSH

Get the engine at running temperature, shut it off, then check the level between 60 and 90 seconds. Haynes has it wrong. Honda automatics have always been checked with the engine off. Personally, I've found the level is pretty much the same, with the engine hot or cold, but I do it Honda's way.