hi all,

i was trying to measure trans fluid temp and read that for the black matte coated trans pan, the emissivity on the IR gun can be left at ~95%. can anyone confirm this?

 

Most here will not. Many members who did not use a proper scan tool to measure transmission fluid probably did not really compare the differences in using an IR thermometer vs. the scan tool readings.

The good news is that the transmission fluid has an temperature range(about 150-170F) that is acceptable for a fill. I would wait until the IR reading is about 140F off the pan which is hopefully an internal 150-170F fluid temperature.

 

not sure what you mean. master mechanic says ~110 F

 

I stand corrected. I was thinking about the Toyota 5 speed automatic in my 2007 Highlander 3.3 V6 4wd filling temperature range.

The RX350 fluid filling temperature range is 104F-112F, but 104F is ideal per the service manual. So I guess a IR pan reading of about 100F would be good.

 

Here is the older 5 speed transmission fluid fill data which I mistakenly posted for the RX350 6 speed transmission. Major mistake there.

 

In a different thread people seem to agree that for the dipstick type temp isn't as important. just check when you know the vehicle is hot.

 

Ah, In the relentless pursuit of perfection!

Feel free to disagree, but there are two levels, max and min and two conditions cold and hot and Specified temperature to measure the level [this is how specifications are]

There is at least 1 qt of level between min and max. I feel lots of people go crazy about keeping the level at MAX. If you go over then it is bad, but below max is just fine as long as you don't fall below MIN. Only only advantage of hitting the MAX level is that in case of a leak [hopefully a small one] you might catch it before it falls below min. Sticking to lubrication part, excess lubricant starts becoming a retardant [moving parts need a thin layer of lubricant between moving surfaces .. they don't need to swim in lubricant]. This cause more loss and more heat and more expansion in volume.

The other misconception [imho] is about sealed or unsealed is as if they are different technologies. The manufacturer has simply decided that it is not a regularly services/monitored item for the designed life of the vehicle. They no longer need to provide access to monitor level. Folks who have vehicles with rear differentials have been living with sealed differential for years. I can speak first hand about 450H where the service is so simple as fill when cold. Drive to warm up and open the filler cap to drain out the expanded volume and plug it back. For 350, there is level relief as I understand it. Even though there is a spec, I very much doubt that the service bays are following it to the T.

Machines are made to operate between a safety range and that is a simple fact. Usually the midpoint is the best. No extra credit for hitting the max end.

Salim.

 

If it works then it works. I just follow the service manual method and so far so good with my 2007 HL transmission fluid level on the dipstick.