New OBDLink mx+ and Transmission Temperature

[Tom 71 Maverick 24]

So, I got my new OBDLink scanner, downloaded the software to my iPhone, and I'm now able to monitor, among other things, transmission fluid temperature. Very cool tool and it should come in handy when I'm towing or just driving around in general.

As for the transmission temperature, I gave the car a long test drive today, mostly highway, and in general, once warmed up, the transmission ran around 195-198 degrees. On my last serious uphill climb, US 27 north out of Chattanooga, it touched on 200 degrees or very close to that. Engine temperature hit the same roughly on that climb, but once I got on more level ground and unloaded the engine a bit, the engine cooled back to 195. The transmission stayed around 198 the rest of the way home.

I have the 4K tow package so there should be a cooler setup for the transmission. And I think I spotted it in front of the radiator, but I also know that the intercooler is stuffed in that space somewhere. Along with the AC coil.

My trip consisted of 4 fairly long hill climbs, up past flat top mountain, back down into the Sequatchie River valley, and then up the other side onto the Cumberland plateau. Stopped for a snack, then reversed the trip. The drive consisted of 1200-1500 foot climbs in the first 4 hills, the last one was maybe 300 - 400 foot, though the temperature was up into the low 90s outside by then.

A pleasant drive, got to learn some of the characteristics of the transmission temperature in use. Toyed around with tow/haul mode to see how it did with engine braking. Cruise control still used the vehicle brakes a bit, but it did get down 1 gear most of the time in tow/haul, and downshifted more vigorously when I was actually trying to decelerate with the brakes. It also gave me a little more gear going up hills, though it also downshifted 1 gear when I was in normal mode on the steep climbs.


Nice scenery overall. Enjoyed my drive. Turned the odometer over 1000 miles.

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[cclark]

Thanks for the great write-up! I'm in the process of trailer hunting and was looking at that exact OBD set up to monitor temps while towing.

 

[rgwalkeriv]

So, I got my new OBDLink scanner, downloaded the software to my iPhone, and I'm now able to monitor, among other things, transmission fluid temperature. Very cool tool and it should come in handy when I'm towing or just driving around in general.

As for the transmission temperature, I gave the car a long test drive today, mostly highway, and in general, once warmed up, the transmission ran around 195-198 degrees. On my last serious uphill climb, US 27 north out of Chattanooga, it touched on 200 degrees or very close to that. Engine temperature hit the same roughly on that climb, but once I got on more level ground and unloaded the engine a bit, the engine cooled back to 195. The transmission stayed around 198 the rest of the way home.

I have the 4K tow package so there should be a cooler setup for the transmission. And I think I spotted it in front of the radiator, but I also know that the intercooler is stuffed in that space somewhere. Along with the AC coil.

My trip consisted of 4 fairly long hill climbs, up past flat top mountain, back down into the Sequatchie River valley, and then up the other side onto the Cumberland plateau. Stopped for a snack, then reversed the trip. The drive consisted of 1200-1500 foot climbs in the first 4 hills, the last one was maybe 300 - 400 foot, though the temperature was up into the low 90s outside by then.

A pleasant drive, got to learn some of the characteristics of the transmission temperature in use. Toyed around with tow/haul mode to see how it did with engine braking. Cruise control still used the vehicle brakes a bit, but it did get down 1 gear most of the time in tow/haul, and downshifted more vigorously when I was actually trying to decelerate with the brakes. It also gave me a little more gear going up hills, though it also downshifted 1 gear when I was in normal mode on the steep climbs.


Nice scenery overall. Enjoyed my drive. Turned the odometer over 1000 miles.

Thanks for the info, just wanted to confirm is this the OBDLink scanner you purchased?

https://www.amazon.com/OBDLink-Bluetooth-Professional-Grade-Diagnostic-Performance/dp/B07JFRFJG6

I just brought my truck to the dealership after I found transmission fluid had overflowed through the vent tube. They told me that it had overheated at some point and all they could do was check the level, clear the adaptive tables and update the PCM.

Needless to say I'm not very confident this won't happen again and want to have a way to monitor the temperature on my longer road trips.

 

[Tom 71 Maverick 24]

yes, that is the one. I did have to download the app to my phone (of course), but there was also a separate Ford "add-on" file that I downloaded. All free. It's a little hard to find, but transmission fluid temperature is in there.

Oh, for some reason, I set my car year to 2023, even though its a 2024. Didn't matter though.

I have not exceeded 200 degrees, just a hair under 200 actually. And it takes a good amount of driving and pretty hot weather to get there. I'm typically seeing more like 185-195. I'll see how it does on my longer trip on Saturday.

 

[Tom 71 Maverick 24]

Gauge view on phone ( I did a little manipulating to get what I wanted on page 1)...

 

[rgwalkeriv]

Awesome, thanks so much for the reply. I went ahead and ordered it so I should get it tomorrow. Were the temperature limits already set or did you do that manually? Just trying to research and figure out the ideal transmission fluid operating temperature.

 

[Tom 71 Maverick 24]

Some of the gauges were already set up with a scale and warning levels. The transmission temperature gauge was not, but once I found the data, I set the scale based on what I'd seen on the internet, and selected numbers that made the scale appear "right". You can gather a lot of transmission temperature data from other forums, particularly ones involving towing, such as F-150, Silverado, and other truck forums. Lots of information there.

There are some fancy charts out there showing the different effects of different temperatures. From what I'm gathering from other forums, you are pushing things a bit as you rise above 220, but that depends on the transmission, the seals, the fluid - I set my gauge for the face to turn yellow at about 205 and red at 230.

Instructions are scarce, but each gauge is configurable as far as size, placement, and the type of gauge, along with colors, font, and title of the gauge. There are 3 pages of gauges. I'm still learning the tool myself.

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