Trans Temp Sensor
JK Enthusiast
Joined: Dec 2007
Posts: 131
Likes: 0
From: Wilmington NC
Really? I would think the supply line going TO the cooler would be best. This would be the temp BEFORE the fluid goes through the cooler. To me this would be closer to the "working" temp of the fluid. After all, isn't the purpose of a trans temp gauge to see how HOT the fluid is getting? The cooler outlet of the transmission would have the highest reading.....other than perhaps inside the converter.
Sorry for the hijack!
JK Jedi
Joined: Feb 2008
Posts: 7,215
Likes: 10
From: Georgia
Oh, ok. Sorry fer the kunfrooshun. My mistake.
JK Freak
Joined: Aug 2007
Posts: 505
Likes: 0
From: Rancho Cucamonga, Ca
I installed in the pan. Having an extra pan sure would have been nice in my case as I had to get er done so I could go wheelin the next day. The location is near the dipstick (deeper section) on the passenger side. If I was doing it again I'd have mounted it a little lower to ensure that the probe was always and completely submerged in the fluid.
Thread Starter
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
RCJeeper,
Thanks for the reply and pictures. I will take your advice and install a little lower.
For the rest of the viewers, the debate can begin if you are still interested in why I chose the pan location over the others.
Thanks for the reply and pictures. I will take your advice and install a little lower.
For the rest of the viewers, the debate can begin if you are still interested in why I chose the pan location over the others.
JK Jedi
Joined: Feb 2008
Posts: 7,215
Likes: 10
From: Georgia
Thread Starter
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
This is what my research has revealed about trans temp probes located in the various points on the 42RLE transmission.
The following is what I have concluded based on my best effort to get the facts.
Line out to the cooler:
This will show temperature of fluid coming out of the trans, but it will be variable with short term spikes as the TC locks and unlocks. Short term temp spikes are normal and not detrimental to transmission fluid life. A probe in this location can lead to unnecessary anxiety.
Line from cooler to transmission:
This will show the fluid after cooling, and will be lower than what the pump picks up from the pan.
In one of the many pressure ports on the side of the transmission:
This will show temp of the fluid only when the particular circuit is in operation. You would have to choose which port to monitor. They are torque converter clutch on, torque converter clutch off, reverse, low/reverse, 2/4, underdrive, overdrive.
This brings us to the pan:
This will show temp of fluid the pump picks up and sends through the transmission. The sump is sort of a "dampener" for fluid temperatures. It reflects the steady state temperature of the fluid. Long term temp rise, which is what degrades the transmission and fluid, will show in the sump. As mentioned above, short spikes in temp as the fluid leaves the transmission are not a factor.
The transmission's factory temp sensor monitors the fluid in the sump. The normal programs in the tranny controller respond to sump fluid temperatures.
The troubleshooting charts and operational limits are based on sump temps.
Some brands of transmission temp gauges recommend an inline probe location IF installing it in the pan is not possible for some reason.
Several local transmission shops recommend the pan location. However, they say most people choose one of the inline locations for ease of installation.
Based on what I have learned, I will be installing the temp sensor in the pan.
The following is what I have concluded based on my best effort to get the facts.
Line out to the cooler:
This will show temperature of fluid coming out of the trans, but it will be variable with short term spikes as the TC locks and unlocks. Short term temp spikes are normal and not detrimental to transmission fluid life. A probe in this location can lead to unnecessary anxiety.
Line from cooler to transmission:
This will show the fluid after cooling, and will be lower than what the pump picks up from the pan.
In one of the many pressure ports on the side of the transmission:
This will show temp of the fluid only when the particular circuit is in operation. You would have to choose which port to monitor. They are torque converter clutch on, torque converter clutch off, reverse, low/reverse, 2/4, underdrive, overdrive.
This brings us to the pan:
This will show temp of fluid the pump picks up and sends through the transmission. The sump is sort of a "dampener" for fluid temperatures. It reflects the steady state temperature of the fluid. Long term temp rise, which is what degrades the transmission and fluid, will show in the sump. As mentioned above, short spikes in temp as the fluid leaves the transmission are not a factor.
The transmission's factory temp sensor monitors the fluid in the sump. The normal programs in the tranny controller respond to sump fluid temperatures.
The troubleshooting charts and operational limits are based on sump temps.
Some brands of transmission temp gauges recommend an inline probe location IF installing it in the pan is not possible for some reason.
Several local transmission shops recommend the pan location. However, they say most people choose one of the inline locations for ease of installation.
Based on what I have learned, I will be installing the temp sensor in the pan.
Last edited by ronjenx; Dec 15, 2011 at 05:57 AM.