Transmission Oil Change - monitoring the trans oil temperature during service
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Joined: Apr 2019
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2014 ML350 4Matic
Transmission Oil Change - monitoring the trans oil temperature during service
I am preparing to change the transmission fluid on my 2014 ML350 4Matic Gas with A89 transmission option. I understand how to go about the job - there are a lot of start-to-end videos and instructions. I'm going to order a service kit specifically for A89 with includes a new pan plug washer, torque converter drain plug, pan bolts, overflow tube, filter, pan gasket, and 10 qts of 'blue' fluid. I also understand that I'll need a pan plug adapter to pump in new fluid (I've already got a hand pump).
The instructions call for the overflow level to be checked and capped when the transmission oil temperature is 113F (45C). I see some people read the temp with a scan tool. But I've seen others do this by reading the temp of the trans oil pan with an IR thermometer.
If you've done this job yourself using a IR thermometer instead of a scan tool to monitor the transmission oil temperature, did you just wait until the outside of the transmission oil pan reached 113F (45C)? Or did you use a different target temperature? I already have an IR gun and am wondering if this is good enough.
Thanks All,
Sam
The instructions call for the overflow level to be checked and capped when the transmission oil temperature is 113F (45C). I see some people read the temp with a scan tool. But I've seen others do this by reading the temp of the trans oil pan with an IR thermometer.
If you've done this job yourself using a IR thermometer instead of a scan tool to monitor the transmission oil temperature, did you just wait until the outside of the transmission oil pan reached 113F (45C)? Or did you use a different target temperature? I already have an IR gun and am wondering if this is good enough.
Thanks All,
Sam
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Joined: Apr 2019
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2014 ML350 4Matic
Related question:
Is the transmission temperature part of the generic ODB2 data package? Will any/most/some generic ODB2 readers be able to access and display this data?
I know many higher-end and MB-specific scanners can access this temperature and much more but am wondering if a basic low-priced all-vehicle generic scanner can.
Thanks
Is the transmission temperature part of the generic ODB2 data package? Will any/most/some generic ODB2 readers be able to access and display this data?
I know many higher-end and MB-specific scanners can access this temperature and much more but am wondering if a basic low-priced all-vehicle generic scanner can.
Thanks
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Joined: Mar 2008
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From: Canada
2012 ML350 Gas
If you go to YouTube there is a video from FCP euro and it shows them using some simple scanner to monitor the temp.
When I did this before on my E46 BMW I just stuck a multimeter temp probe inside the fill plug to check the temp. However since you only got a drain plug here, can’t really do that.
Not looking forward for this job also. Anyone know if there is a low trans fluid level sensor ? I worry that the stick that is pointed up to indicate proper fill level is going to fall off and level won’t be accurate.
Really wish there was a dipstick.
When I did this before on my E46 BMW I just stuck a multimeter temp probe inside the fill plug to check the temp. However since you only got a drain plug here, can’t really do that.
Not looking forward for this job also. Anyone know if there is a low trans fluid level sensor ? I worry that the stick that is pointed up to indicate proper fill level is going to fall off and level won’t be accurate.
Really wish there was a dipstick.
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2014 ML350 4Matic
In that video, he is using an iCarsoft i980 Mercedes-specific scanner. It costs $150-200. There are several other MB-specific scanners that will report the trans temp. I am curious as to two other options:
1) is this data available via an inexpensive generic ODB2 scanner? I can't seem to find the proper code for the ATF temp for Mercedes so I have no way to test this.
2) Will pointing an IR Thermometer at the pan give a a reading close to the temp of the fluid inside? Or should I assume the pan is a little cooler and aim for 110F? Will that be good enough?
1) is this data available via an inexpensive generic ODB2 scanner? I can't seem to find the proper code for the ATF temp for Mercedes so I have no way to test this.
2) Will pointing an IR Thermometer at the pan give a a reading close to the temp of the fluid inside? Or should I assume the pan is a little cooler and aim for 110F? Will that be good enough?
Last edited by sams_6; Feb 8, 2022 at 02:25 PM.
Thread Starter
Junior Member
Joined: Apr 2019
Posts: 23
Likes: 7
2014 ML350 4Matic
Thanks. I didn't expect a quantified "transmission temp" reading but thought that maybe it was reported raw to the ODB2 bus via some Mercedes-defined PID.
I'm curious what people think about using an IR gun to take a reading off the transmission oil pan.
I'm also researching a MB-specific scan tool.
I'm curious what people think about using an IR gun to take a reading off the transmission oil pan.
I'm also researching a MB-specific scan tool.
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Joined: May 2018
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From: Cape Town, South Africa
ML350 BlueTec W166 - C250d W205 - GLC250d - C43
Good luck with this, it's quite a job... I did this just more than a year ago and also used an IR thermometer, this works fine in my opinion. Checked the pan temperature to go to 46C and to be sure the valve opens. The most difficult of the entire job was to properly knock over or dislodge the overflow tube in the pan. This looks simple in the videos but took some fiddling.
