Transmission Temperature Gauge

When towing, your transmission can generate extra heat from the load. Heat kills automatic transmissions. Adding coolers will help, but how do you know if the transmission is overheating? A transmission temperature gauge!

I installed a gauge I bought at the local parts store.

The key to a temperature gauge for the transmission is range. A good range for the gauge is 100-300 degrees. Most gauges I found started above 100, but my transmission sometimes runs below that. The recommended running temp is about 150 degrees, so if the gauge starts above that, it won't be very effective.

The gauge was a fairly easy installation- a single wire from the sending unit to the gauge in the cab. The gauge needs a +12v source, preferably switched, and a ground.

I installed my gauge in my console- it is visible if I don't have it full of junk and the console is still usable. Alternatively, the bracket that comes with most gauges can be used to hang it under the dash. Other members have installed a pillar gauge pod.

Here is my gauge-

The sending unit placement can affect your readings. The easiest install is on the rubber line just before the factory aux cooler. I did mine like this- it is a brass T with hose barbs on each end, the sensor in the middle. Notice there are two wires there, one connects to the sending unit, the other is a ground wrapped around the T fitting to provide a ground. The sensor works off a ground source.

However, it has been argued that it is not the most accurate place to put the sensor because it doesn't accurately represent the temperature the transmission sees. I have since moved the sensor to the pan. I used a B&M drain plug kit, drilled a 1/2" hole in the pan. The sending unit threaded right in to the adapter. It doubles as a drain plug, all I have to do is remove the sending unit.

I recommend that you install a temperature gauge before you add an additional cooler, you may not need one. My transmission runs plenty cool without a 2nd aux cooler, but I watch my gauge when towing.

 

[MountaineerGreen]

Aldive did a bit different temp gauge install, used a gauge pod for his A pillar.

Good pictures of a secondary cooler and temp sending unit-

http://www.explorerforum.com/forums/showthread.php?t=141191

EDIT: And another nice install

http://www.explorerforum.com/forums/showthread.php?t=179884

 

[ProjectAviator]

What about the 95 & 96 without the aux tranny cooler. I picked one up from a KIA sedan that was our comp car while I was at Wyotech. I have the Autometer Z series mounted in a double pillar pod with a engine temp. Just waiting for warmer weather to put in the cooler & tranny temp gauge.

Tim

 

[MountaineerGreen]

What about the 95 & 96 without the aux tranny cooler. I picked one up from a KIA sedan that was our comp car while I was at Wyotech. I have the Autometer Z series mounted in a double pillar pod with a engine temp. Just waiting for warmer weather to put in the cooler & tranny temp gauge.

Tim

I still recommend putting the sender in the pan- that is the temperature most of your transmission sees. There is a pressure test port on the side of the transmission you can use too. When you install the cooler, you can tee into the line like I did, its all what you want to do.

 

[SnakeCharmer]

I have been considering adding a trans temp guage to my Sport Trac but any install I did would have to pretty much look factory and be accomplished without cutting anything up. Pillar pod is out of the question and I cant have it hanging under the dash so I was wondering about a column mount. The column trim seems to be pretty similar to the SN95 Mustang so I wonder if the pods made for those would fit the Explorer column. Anybody know for sure?

Im also wondering at what point a 2nd auxillary cooler becomes nessecary. I have the factory aux cooler and it seems to be pretty good size and since the heaviest thing I regularly tow is my bass boat that probably isnt much over 2000# loaded I would bet its sufficient. However, I sold my little pop-up and we have been knocking around the idea of a travel trailer of some sort. Probably something hovering around 5000#.

 

[MountaineerGreen]

At 5K a cooler becomes a must, IMO. The v6 trannies just wont hold up without additional cooling. I would run one no matter what on a v6 drivetrain. Coolers are too cheap and transmissions are too expensive to not!

I would like to see some additional gauge mounts added to this. I can't say if it will work or not, but you can try. When you do post pictures!

 

[SnakeCharmer]

At 5K a cooler becomes a must, IMO. The v6 trannies just wont hold up without additional cooling. I would run one no matter what on a v6 drivetrain. Coolers are too cheap and transmissions are too expensive to not!

Maybe I wasnt clear. I have the cooler in the radiator as well as the aux cooler mounted in front of the radiator that comes with the factory tow package. My question is at what point a 2nd aux cooler (or 3rd cooler I guess you could say) becomes nessecary.

 

[MountaineerGreen]

Maybe I wasnt clear. I have the cooler in the radiator as well as the aux cooler mounted in front of the radiator that comes with the factory tow package. My question is at what point a 2nd aux cooler (or 3rd cooler I guess you could say) becomes nessecary.

Sorry, I wasn't clear either. I would add a 3rd cooler regardless. Many have done so already. If you are going to tow the pop up camper, I definitely would. It cost too little to do so compared to the cost of a transmission.

I have seen coolers at parts stores and on web sites for around $50. The install isn't that involved, and the added cooling will help keep your transmission in good shape.

 

[SnakeCharmer]

Sorry, I wasn't clear either. I would add a 3rd cooler regardless. Many have done so already. If you are going to tow the pop up camper, I definitely would. It cost too little to do so compared to the cost of a transmission.

I have seen coolers at parts stores and on web sites for around $50. The install isn't that involved, and the added cooling will help keep your transmission in good shape.

OK Cool. I guess were on the same page. And my pop up was probably lighter than my boat and never concerned me much. I sold it. We are now looking at travel trailers (not pop-ups) in the 22ish foot range. Thats why Im considering extra cooling. I will probably go ahead and do it just for good measure. I have installed plenty of coolers in my day so no problem there. However, I usually go with with AN fittings and a combination of braided and hard line since I dont trust rubber line so $50 aint gonna cover it and gets a little more involved. I noticed that the factory cooler uses rubber line and hose clamps so I will probably end up redoing the whole thing.

 

[410Fortune]

wait wait wait, first monitor the temps the transmisison is running at before you just add coolers.

I would prefer to run a larger or more efficient cooler in place of the aux one then I would run 3 in series, less chances for hoses and fittings to develop leaks, also alot cleaner and easier to get the fan to pull air through.

But if your trans is running at 150 degrees with 2 coolers and while towing then why add another cooler? IMO its not needed.

 

[SnakeCharmer]

wait wait wait, first monitor the temps the transmisison is running at before you just add coolers.

I would prefer to run a larger or more efficient cooler in place of the aux one then I would run 3 in series, less chances for hoses and fittings to develop leaks, also alot cleaner and easier to get the fan to pull air through.

But if your trans is running at 150 degrees with 2 coolers and while towing then why add another cooler? IMO its not needed.

all good points. Guess I was just after a basic rule of thumb, like the factory tow package cooler is good fo xxxx towing capacity or something along those lines.

 

[410Fortune]

It just doesnt work that way, too many factors, gearing, climate, load, condition of the cooling system you have, etc. A trans temp gage is the best place to start.

Also OBD_II Ford auto transmissions already have a heat sensor in the pan, you can get the temp from the computer or tap into this wire to run a gage, as well as add a sensor in your system.
Many race trucks or well built rigs will use more then one trans temp sensor, so they can monitor temps in the pan as well as pre or aft the coolers

 

[bill55az]

If you want a killer aux cooler, look in the junkyards for older Ramchargers and possibly Dodge trucks. I saw one that at first looked like the AC condensor, but it wasn't. It was the biggest tranny cooler that I have ever seen, covered almost all of the radiator.
Make sure to get one that matches your cooling lines size. Older ones are 5/16, newer ones are 3/8".
Or, get one from the 1 ton or larger Ford trucks, those are pretty good size as well. We have several self-pull yards here in AZ and they occasionally have 50% off sales. PickNPull has a website, and they are in a lot of states. Ecology is mostly in CA with one in AZ. Any size at Ecology runs about $15 or half that on one of the sale days.

 

[duke16]

Moutain, when you moved the sensor from just before the aux cooler to inside the pan, about how much of a difference in temperture did you see? I'm curious as to how large of an impact it makes.

 

[dman726749]

I would like to see some additional gauge mounts added to this. I can't say if it will work or not, but you can try. When you do post pictures!

Here is my gauge and temp sensor install.....its an f150 pod that goes, and the sensor is installed inline right before the line goes into the rad for cooling....

http://www.explorerforum.com/forums/showthread.php?t=165895

 

[BrooklynBay]

Mountain, when you moved the sensor from just before the aux cooler to inside the pan, about how much of a difference in temperture did you see? I'm curious as to how large of an impact it makes.

That is a good question. A lot of people would want to know the answer. I'm sure that it only varies by a few degrees, but it would be a more accurate reading.

 

[MountaineerGreen]

Surprisingly, the location of the sensor had a huge impact on my readings. When it was before the secondary cooler, my gauge usually was right around 100* around town, lower on the highway. When towing, it would get up to 160* climbing a steep hill. I knew that couldn't be right.

Now, it runs 160 or just slightly under on the highway, 170 or so in town, and about 200 when towing. The sensor in the pan has a huge effect on the temperature, and I feel that the sensor in the pan more accurately represents what the transmission parts are seeing temperature wise.

 

[duke16]

Surprisingly, the location of the sensor had a huge impact on my readings. When it was before the secondary cooler, my gauge usually was right around 100* around town, lower on the highway. When towing, it would get up to 160* climbing a steep hill. I knew that couldn't be right.

Now, it runs 160 or just slightly under on the highway, 170 or so in town, and about 200 when towing. The sensor in the pan has a huge effect on the temperature, and I feel that the sensor in the pan more accurately represents what the transmission parts are seeing temperature wise.

Wow, that is a big difference. Where it was before, before the aux cooler, was that before or after it had already gone through the radiator?

 

[IAmTodd]

Can always go a little custom:

 

[Stic-o]

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