Trans fluid fill temperature stupidity

[kdad]

Hi - After draining the transmission fluid, I misread the hot fill instructions. Instead of filling at 40-50 deg, I filled in the 55+ deg range. I only realized it after cleaning up everything.

The vehicle shifts smoothly otherwise. Should I bother checking the fluid level in the proper range?
In this case, should I expect the trans to have more or less fluid than designed? It would be more convenient to drain the excess if I decide to check the fluid.

Thanks.

[tlaspec]

Fluid expands at higher temp so it be slightly less than requirement. I would check and fill again at right temps just so not to think about it but thats just me.

[Tomcat_F15_STL]

Agreed.

Start from cold. Pull the plug & fill or allow to drain when in the 30-40C temp range.

[stocktree]

Forget about it. It's alright. Do you know how negligible the fluid will expand, with a 10 or 15 degree temp change?

[kdad]

I don't think fluid expansion is a big deal. It's more about transmission internal volume changes due to temperature. Eg selenoid opening up new passages that would cause the fill to take more or less fluid

[stocktree]

Originally Posted by kdad

I don't think fluid expansion is a big deal. It's more about transmission internal volume changes due to temperature. Eg selenoid opening up new passages that would cause the fill to take more or less fluid

There aren't just random solenoids sending fluid to nowhere. The only thing that is possible, is a solenoid for cooling lines. But I've never seen a transmission designed like that.

[tfunk88]

I’d leave it and just do it between 40 and 50 next time. 5 degrees over ain’t gonna make THAT much difference.

Also if you do decide to redo it don’t open up the fill plug without the car running, otherwise a bunch of fluid will pour out.

[srybicki]

My was filled at around 55 as well over 12k miles ago. Leave it

[kdad]

Good answer 😄

[Tomcat_F15_STL]

Be cautious of opinion-shopping.

[stocktree]

Originally Posted by Tomcat_F15_STL

Be cautious of opinion-shopping.

Let's hear your opinion

[underp2]

Why can't they just tell you how much to add? If you drain it and add a known volume of room temperature fluid, they should be able to calculate how much fluid that would be at 45°C. Seems overly complicated. Do you add wildly different amounts every time?

[stocktree]

Originally Posted by underp2

Why can't they just tell you how much to add? If you drain it and add a known volume of room temperature fluid, they should be able to calculate how much fluid that would be at 45°C. Seems overly complicated. Do you add wildly different amounts every time?

When you drain the pan, there is still a lot of fluid in the valve body, torque converter, lines, etc, that doesn't get drained. Does the same amount of oil drain out each time? It's probably close, but not exactly the same.

[suitedcboy]

Exactly! The cooler circuit control valve that regulates pressure in cooler circuit, the exit point from torque converter, may seal 100% or 25% You may drain your fluid 15 minutes after shut down and have a valve with no leakage or let it sit overnight with a valve that has some leakage and converter is only half full and 2.5 litres extra drains. The assurance of full is to add till it runs out at a defined temperature range. Take away th torque converter and the fluid fill could be defined. If TC had a drain (this stopped in the 70s) and the fill could be predictable.

[spit]

guys, there is an easier way to do it if the gearbox has no leaks, you just pour in as much as you drained.
One fact is that you need to measure how much old oil you drained

[Tomcat_F15_STL]

It’s a bit confounding to me to witness so many people fighting and kicking and screaming about doing a documented and straightforward procedure. WTH?

Run it to specific temperature, pull the plug and either allowed to drain, or top it off.

What is so divisive about this task?

🤔