Transmission temp gauge

[sunnysideup_lj]

I am getting ready to install a transmission temp gauge on my 06 LJ. It has the 42rle tranny. I have read other installs on this forum and it looks like most are welding a bung in the pan for the sensor.
My question is, do you get the most accurate reading from that location? Or is it better to run a sensor in the transmission line before it reaches the cooler? Also what temps should this transmission run at?

 

[MountaineerTom]

To me it makes sense to have it in the pan. That’s where the fluid is getting pulled from so why not know what the temp of that is.

If you had it before the cooler, it’s obviously going to show a hotter temp.

If you wan to get really picky, you could put two sensors and a switch. One to read the pan, one to read the pre-cooled temp.

One in the pan is really all you need though.

 

[Vinman]

If you wan to get really picky, you could put two sensors and a switch. One to read the pan, one to read the pre-cooled temp.

Thats exactly the way I monitored tranny temp in a previous Rubicon, two sensors with one gauge and a switch to check pan temp as well as the temp of the fluid just before it entered the cooler.

 

[sunnysideup_lj]

Thats exactly the way I monitored tranny temp in a previous Rubicon, two sensors with one gauge and a switch to check pan temp as well as the temp of the fluid just before it entered the cooler.

Great idea! Best of both. What kind of temps did you see from both locations?

 

[Vinman]

Great idea! Best of both. What kind of temps did you see from both locations?

It’s been about 13 years since I sold that TJ but I believe the hot side was around 180-210 and the pan about 150-160. The pan temps usually stayed pretty consistent while the hot side constantly varied. Climbing a hill on the highway? Temp shoots up for a few seconds. Accelerate hard? Temp shoots up again. But the pan temp was relatively stable. I also had the largest auxiliary tranny cooler I could fit ahead of the rad, I think ot was rated for around 20,000 LB GVW