ScanGauge ATF temperatures for NX

[Fatwilliam]

It appears that there are two sensors for ATF temperature. One in the pan and one in the pipe from the torque converter. The ScanGauge site only lists one X gauge for Pajero. I have set this X gauge up and it displays a temperature between 65 degrees C and 75 degrees C under low load conditions. The temperature increases quickly when accelerating and decreases quickly when speed is then constant. This suggests to me that the sensor being monitored is the one in the pipe. I sent a question to ScanGauge asking if it was possible to monitor the second sensor but they say they only have parameters for one. Really frustrating!! In one of the posts relating to Ultragauge a poster "m and m" says he is monitoring both sensors, which suggests that both sensors can be accessed. Have any of you out there managed to set up an X gauge for both?

[symo]

https://www2.pajeroclub.com.au/forum/showthread.php?t=65510

https://www2.pajeroclub.com.au/forum/attachment.php?attachmentid=42567&d=1570568985

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[Fatwilliam]

Thanks Symo. Whoohoo!! I will try the X gauge for the pan in the morning.

[symo]

Slight variation between the two temps on my NX but I’m only towing an 8x5 1500high luggage trailer with camping gear and 4 mountain bikes.


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[Fatwilliam]

X gauge for PAN now programmed. In the morning I will check what temperatures are reported before starting the engine. I saw some discussion on other threads about the correct temperature offset. Currently showing 37 degrees C for both ATF and PAN, 30 degrees C for coolant. I Have a 2300kg caravan so I will monitor temperatures when I can get away.

[Ian H]

When towing a van that size, watch the pipe temp go up when you try towing in 5th and then drop back to 4th and see how that makes a big difference as the TC locks up.

The TC lock up kit sold by MM 4x4 makes a huge difference to the trans temp and is a great addition to have when towing.

[Fatwilliam]

Just checked the morning X-gauge readings and edited the offset to -50C (I initially set it to -40C which is what is shown on the ScanGauge site). The car was parked in the garage overnight. Current readings, Ambient 10C, Coolant 14C, Pan 14C, Pipe 14C. Interesting. There is presumably some thermal lag between engine and transmission when compared to ambient. More importantly is appears to confirm that the correct offset is -50C. (MTH should terminate with FFCE)

[nj swb]

The car was parked in the garage overnight. Current readings, Ambient 10C, Coolant 14C, Pan 14C, Pipe 14C. Interesting. There is presumably some thermal lag between engine and transmission when compared to ambient.

Yep. Coolant and trans have large thermal mass, and probably somewhat insulated under the bonnet / under the car. Would still be cooling to ambient. The ambient air sensor has negligible thermal mass, in behind the grill - little insulation from ambient, as you would expect.

First thing in the morning, I often find coolant a few degrees warmer than ambient, and transmission temps (both of them) a little warmer again.

[Fatwilliam]

Finally had the opportunity to get away for a few days with the van. I checked out the behaviour of the transmission temperature under various conditions.


The temperature in the pipe climbs rapidly under acceleration with the pan lagging way behind.


Cruising at 100k in 5th showed the pipe substantially hotter than the pan. Dropping back into 4th brought both temperatures together, maybe 1 degree difference at the most.


IanH, you were spot on with your advice.
Towing in 4th is clearly the go. Let the torque converter stay locked up and keep the slippage out of the equation.


I assume that limiting waste energy will translate to improved fuel economy. Has anyone measured this one?

[nj swb]

IanH, you were spot on with your advice.
Towing in 4th is clearly the go. Let the torque converter stay locked up and keep the slippage out of the equation.

I assume that limiting waste energy will translate to improved fuel economy. Has anyone measured this one?

Limiting waste energy? All else being equal, without doubt. Measuring it would be a different issue.

The difference between 4th & 5th is a little murkier. Towing in 5th at higher load but lower revs can be more economical - depending on how much higher the load is, and how much lower the revs are. Generally, if your transmission is quite hot and staying hot in 5th, you'll be better off all around in 4th - better fuel economy over all, and better for your transmission fluid.

Use an intelligent aftermarket lockup kit (like MM 4x4's auto-mate ) and you'll get the best of both worlds - better economy in 5th when conditions allow, and less stress in 4th when conditions dictate.

If auto-mate isn't in the mix, tow in 4th. Better to use a little more fuel than risk a transmission repair bill.

[Dicko1]

Having had the ecu remapped and installing the auto-mate I find towing in 5th on the flat or even slight inclines very easily done. Tow around 22ookg. Worst fuel figures I,ve seen are around the 16ltres/100klm mark...mind you...head winds suck up the fuel. Return trip was around the 13 liter per 100klm mark.. That is sitting on 100-105kph. Paj does it relatively easy. Having the motor remapped has helped tremendously.
As I do a lot of towing I intend to buy a smaller car for running around town and set the Paj up exclusively for towing/touring. Third row seats went many years ago and soon the second row will disappear as well.