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Discussion Starter #1
One thing Jeep missed out on the JK was a transmission temperature gauge. With all the talk of JK transmissions getting hot, especially on the Unlimited, I was interested to see what my tranny temp was.

So, I installed a B&M Transmission Temp Gauge. Installation was straight forward. I mounted the gauge on my Daystar upper dash panel rather drilling holes in my dash. I mounted the sensor in the return cooler as recommended by B&M. I mounted towards the front as this was the easiest place to cut the line and work on it. I connected the back light up to the dash dimmer circuit.

The gauge is a B&M 80212, which comes everything you need, gauge, pod, temp sensor, etc.

Of course as soon as I finished it started raining, sun disappeared and temps dropped by 20°F, but it still gave me a good indication of tranny temps. On the highway with the tranny locked up I never broke about 140°F, in stop and go driving it got to about 160°F. Nothing that looked bad at all, although I was more concerned about off-road temps and for those times the tranny works harder.

At least I will now know the transmission temp and be able to see when it starts getting hot.



 

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Discussion Starter #2
A quick double check with an IR thermometer shows the return line to be the exact same temp as the gauge, and the pan about 30-40°F hotter, which is about what I'd expected to see.
 

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Nice clean install...good job:beer:
 

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Nice clean install...good job:beer:
Good idea.

I wish that someone would come up with an A-pillar gauge gauge cluster. I'd like to see oil temp and pressure also.
 

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Nice job Phil. I have installed a cooler on mine, but no gage yet.

Never mind the money, but where do you find the time to do all this stuff to your JK? You are definitely on a mod hot track. :beer:
 

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Good idea.

I wish that someone would come up with an A-pillar gauge gauge cluster. I'd like to see oil temp and pressure also.
Great job Phil, looks good.

The A-pillar isn't mounted well enough to support gauges, I was thinking about mounting my gauges there in cups when I found out how flimsy it really is. Now, someting to replace the existing cover would be good, but there again not much to fasten it to.
 

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What do the consider "to hot" when you mount the sensor in the return line from the cooler? I always thought you wanted it in the line coming out of the tranny, going to the cooler, since that ones the hottest.
 

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Discussion Starter #12
What do the consider "to hot" when you mount the sensor in the return line from the cooler? I always thought you wanted it in the line coming out of the tranny, going to the cooler, since that ones the hottest.
The best places to measure tranny temp are the pan or the return line. The out line is going to show the temp leaving the TC and not a good indication of operating temps of the tranny. The pan will give you a good indication of the overall tranny temp and is a common place to measure, but will be slow to change. The return line is what is going back into the pan and will be a little lower than the pan, but will respond much faster to changes in temp.

As to what is too hot, it will depend on the speed of the vehicle to an extent, as when you are at highway speeds the return line temp is much closer to the pan temp, when you are going slow the pan temp will be higher by a higher margin than the return line. More importantly you need to monitor the trend and changes in temp, in the return line you will see these faster.

I'd rather not see temps over 200°F for prolonged periods, as the ATF degrades much faster at higher temps, 175° is about ideal operating temp and the pan is running below this on mine nearly all the time.

I've yet to break 140°F on the return line in stop and go traffic, and the best I can tell the pan temp is about 170-175°F. On the highway it runs at 120°F, and again the best I can tell the pan temp is about 135-140°F.

These are all with an ambient air temp around 90°F.

I'll get the first chance to monitor it off-road next weekend and will be interested to see how much hotter it gets.
 

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Let me know how it does offroad, as I'm looking to get a cooler, but wasn't sure if I should get one with its own fan, or the same one you have. I like yours better cause its obviously cheaper:) My main concern was the tranny temp while running a slow moving trail.
 

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Discussion Starter #14
During two days of wheeling, moving at real slow speeds and working the vehicle hard in 100-105°F heat it never broke 160°F, and sat between 140-150°F most of the time.

Now that is the return line after the fluid is cooled, but even allowing for a 40° increase in pan temps, that is still acceptable.

I was please to see how well the tranny kept cool.
 

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Discussion Starter #17
how much trans fluid came out?
Very little, maybe a pint or so if I recall, but you will need to make sure the level is correct. I since switched to a pan mounted sender and an Autometer gauge, but the B&M gauge and sender worked just fine.

A sender on the return line will show changes in temp quicker than a pan mounted sender. A pan mounted sensor will give you more of an average reading and will be slower to respond to temp changes.

http://www.jkowners.com/forum/showthread.php?t=3784
 

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:) I've got both-Hot out and Cool in-



:smokin: JIMBO
 

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Very Nice PhilD I need to get a trans cooler next And install a Guage, Good Job!
I will have to copy cat this thanks.:smokin:
 

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Phil,
i just wanted to clarify, so if i missed it, sorry... but you added the temp gauge after you added another tranny cooler, right?

reason, i'm just a little curious how it looks with the stock cooler.
 
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