Checking 10R80 fluid level

[EFI]

So I went to the dealer to have them check the trans fluid level and see if it needed topped of after seeing many stories with the pan being underfilled from the factory. I went to drop off the vehicle, and the tech said he needs to go out and drive the car until the fluid temp got to about 200* to properly check.

I told him there's no way he gets to that temperature just driving around normally as I can drive around for hours and the temp never gets above 185*. He would have to drive at WOT for like 5-10 minutes to get there and I said I didn't want to have someone else constantly beating on my car and possibly getting in trouble for speeding or crashing.

Then they said they can't take an accurate measurement without the fluid at a certain temp. This seems a bit ridiculous, as it means everytime the fluid needs checking someone has to go out and beat on the car WOT for a while just to get it there. Doesn't make much sense.

Is there no way to get an accurate reading with the fluid at a lower temp?

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[sdsteele2]

According to the service manual they are correct. The full operating temp to check the fluid is 206-215F. They could eye-ball the mini dipstick and get an approximate level.

 

[bankyf]

Put the trans in drive, hold the brake and take it up to 1500-2000 RPM. Temp will come up quick. It's the only way I've found to get many of them up to temp to check levels or properly flush them.

 

[EFI]

Put the trans in drive, hold the brake and take it up to 1500-2000 RPM. Temp will come up quick. It's the only way I've found to get many of them up to temp to check levels or properly flush them.

That's interesting, because I often travel long distances with the car, and cruise around 2000rpm for hours and I've never seen the trans go over 192-194*. Yes goes up quickly to ~190*, but as soon as the thermostat opens it doesn't budge much after that. Maybe if I sit still (vs. traveling at 80mph) will provide less cooling, but even then the fans will be on full blast cooling the trans.

What temps can you achieve by doing that?

 

[bankyf]

That's interesting, because I often travel long distances with the car, and cruise around 2000rpm for hours and I've never seen the trans go over 192-194*. Yes goes up quickly to ~190*, but as soon as the thermostat opens it doesn't budge much after that. Maybe if I sit still (vs. traveling at 80mph) will provide less cooling, but even then the fans will be on full blast cooling the trans.

What temps can you achieve by doing that?

I believe the torque converter is what is generating the heat while doing what I described. When you are cruising it is likely locked up. Also the airflow is helping to cool. I have never tried to see how hot I can get, but I can easily and fairly quickly(compared to driving) get it up to the specified range. I fact, if you aren't careful it's easy to overshoot.

 

[andrewtac]

I believe the torque converter is what is generating the heat while doing what I described. When you are cruising it is likely locked up. Also the airflow is helping to cool. I have never tried to see how hot I can get, but I can easily and fairly quickly(compared to driving) get it up to the specified range. I fact, if you aren't careful it's easy to overshoot.

This. Torque converter is generating the heat. Holding the brake while in gear and some rpm will heat it up. In my old race car I'd put it in neutral at red lights as I could watch the temp rise even at idle.

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