C4 Temp Gauge Sensor Location

[Bukin 67]

I'm installing one for the first time. Just wondering where is the best location?

 

[Mountain Ram]

Good question... Is it an in line deal to put in cooler lines? What gauge are you using?

 

[Bukin 67]

I'm using the Autometer Ford Racing with the screw-in temp sender.
http://www.autometer.com/media/manual/2650-1133-00.pdf

 

[Broncitis]

I've seen this question debated time and time again and there seems to be no clear consensus.

Some want it in the pan, some on the feed line from the cooler, and some on the return.

My thinking on this is that I want to know how hot the fluid gets since that determines when it smokes. It does not matter where in the system it is, at a certain temp, the fluid is burnt. Therefore, I put a sender on the outlet to the cooler.

I also put another sender on the return after the cooler. I wired these into a switch so I can toggle between the two senders and read it off the same gauge. This allows me to see how hot the fluid is, worst case, and also to see how effective the cooler is and wht the return temp is to the pan.

I have since picked up a nice rotary swith with multiple positions which I may use in the future to be able to check in on other system with a single gauge (PS, Oil, trans pan, etc.). I'm not a fan of a dozen gauges all over the place, but would like to be able to check on a system when I am working it hard or suspect an issue.

 

[Bukin 67]

I can totally understand wanting to completely know what's going on with the tranny cooling system. I just want to be able to keep tabs on it. I've heard different danger zone temps too. 200-210 seems to be the consensus for a c4 normal operating temp.

 

[Broncobowsher]

The standard location is the pan. New trucks with a temp gauges use pan temps. It is the closest you can reasonably get to the frictions and seals that you should be worried about cooking.

Put it in the cooler in and all you see is how hard the torque convertor is working. Even with a working cooler it will always appear hot any time you are on the throttle hard.
Put it in the cooler out and you just see what the return temp will be. Restrict the flow and the oil will spend more time in the cooler and come out colder while the actual temp in the transmission climbs.

 

[roderickl]

According to one of the transmission cooler companies (don't remember which), at the output of the transmission cooler, so you can make sure the fluid is properly cooled.

Other companies mention installing in the pan.

Although I have yet to install mine, I bought 2 senders and a switch. I plan to install one in the pan and one just before the cooler input.

If I were to install only one, it would be in the pan. I want to have some idea of the average sustained temperatures. In the fluid flow order, the pan is after the cooler about to enter the transmission. There will be some heat soak from the transmission, but it will still be an indicator of cooler effectiveness.
I typed the above response before I saw the response from Broncitis.
If you expect to approach extreme temperatures often, between after the transmission on the way to the cooler would probably be best. If not, sustained temperatures can be estimated using a pan mounted sensor.
I agree with the Broncitis view on burnt fluid and I also think that sustained temperature is important.
I am going to stick with my pan preference for my situation, although I do not disagree with Broncitis.

 

[Broncitis]

I can totally understand wanting to completely know what's going on with the tranny cooling system. I just want to be able to keep tabs on it. I've heard different danger zone temps too. 200-210 seems to be the consensus for a c4 normal operating temp.

200-210 seems just a bit high for a normal op temp in the pan, but they do vary some even between similarly equiped Broncos. 180-200 would be better if possible for normal driving, 200-210 off road with some intermitant spikes of no more than 220 on more difficult obstacles seems more what what I'd be aiming for.

The pan does offer a more stable or average temp if only measuring one location, and will be more representitive of the entire mass of parts in the trans, but it will not show the max temp your fluid is reaching which is really what determine when the fluid gets scorched which is another failure issue.

 

[Broncitis]

When I install the rotary switch when I get this rig back together, I will liklely add a pan mount as my default reading, then I can check others as needed. However, the 2 sender setup as described worked well for me, but you do need to know what and how it is reading the temps to put them into a different perspective than what a pan mount will read on its own.

With the way my senders are installed, I am really not worried about a restriction of flow as the fittings they are in are less restrictive than the feed and return lines. The return is really installed more just for curisoity to see how effective the cooler is, but can also indicate when the fan may not be working or if it might be obstructed with dirt or mud.

 

[dave67fd]

Per the gauges instructions (Installation 6B) it says to mount in the pan.

 

[jw0747]

Many, many differing opinions on this but here is a trailering expert's opinion which makes sense. It's a simple install and doesn't require drilling a hole in your pan. The filter mentioned in write-up below is optional. Mine is wired like this measuring temp going from the trans forward to the coolers (without the filter) and provides me what I need. If you elect to go this route you would need an inline brass fitting for the cooling line that would accept your sensor.

http://www.etrailer.com/question-22793.html

 

[Viperwolf1]

For all those that think having the temp gauge sensor in either cooling line is the best place, you should know that the majority of the trans fluid does not get sent to the cooler each time it cycles through the trans.

 

[Letsgocrawling]

For all those that think having the temp gauge sensor in either cooling line is the best place, you should know that the majority of the trans fluid does not get sent to the cooler each time it cycles through the trans.

Maybe Vipers comment had something to do with where i was told to put it, the pan was the answer. Just saying what the tranny and motor guy said. The temps run from 175 cruising on the street to 185 rock crawling, 195 pushing it in 4 wheel on the dunes. Did see 240 when i did a long #4 obstacle in high range by accident

 

[Broncitis]

For all those that think having the temp gauge sensor in either cooling line is the best place, you should know that the majority of the trans fluid does not get sent to the cooler each time it cycles through the trans.

I agree, but the pan will also not tell you the actual max temp that the fluid reaches since much of the fluid in the pan (especially in a deep sump pan with larger volume) does not cycle immediatly or withing the same timeframe you referenced either.

However, since the fluid that does go to the cooler just cycled through the pump and convertor, won't this provide the reading for the actual max temp the fluid has reached (the sender does not need to sample all of the fluid, just some of what just came out of the convertor).

Based on this theory, I would think if you want the more steady overall "average" of the entire trans, measure at the pan. If you want the max temp of the fluid, measure at the cooler feed.

My thought has been to watch for a max condition, not an average one. In a similar way of thinking (but not quite as extreme perhaps), consider gauging RPM where you do not want to exceed "X" RPM. The average RPM over the last 10-20 seconds is really irrelivant.

IMO, cooler return reading is really only good as a nice to know or intersting observation of cooler effeciency for the most part, and would certainly not be my choice if only one location is sampled.

It would be interesting to see all three locations data-logged on a graph to see how they trend against each other. I'll have to see if RanSil can rig something up like this since he is a data geek that way (he has multiple wireless thermocouples in his electric smoker and logs temps for BBQ ribs and pork butts). ;D

 

[jw0747]

No doubt the place where you elect to install the sensor on your Bronco is always the best. If my cooling line mounted sensor indicates an acceptable operating temp I'm not worried that my transmission is burning up because the sensor's not mounted in the pan.

 

[Bukin 67]

I am running a deep pan as well. With just one senspr mounted there it looks like I'll have to do some assuming as far as what my max fluid temp really is.

Thanks for the additional normal running temp info. Racing, I should probably see 190-200 when I'm really on it. Cruising I should be closer to 180. Pretty much like water temp ranges.

 

[joe]

i was always under the assumption that the best place was the pan because that's where the fluid is feed into the trans???

 

[357Bronco]

A long time ago I bought a kit that put the sensor in the output cooler line. After running it very hard I noticed the temp was a little high and that I was loosing fluid out the overflow and the trans didn't seem to act right. I had no issues before the gauge and sender install. I took it apart and noticed how small the adapter necked down for the sensor was. Moved the sensor to the pan and all was good. Could have been a fluke, I don't know, but there was definitely a restriction with that set up I had.

 

[Bukin 67]

A long time ago I bought a kit that put the sensor in the output cooler line. After running it very hard I noticed the temp was a little high and that I was loosing fluid out the overflow and the trans didn't seem to act right. I had no issues before the gauge and sender install. I took it apart and noticed how small the adapter necked down for the sensor was. Moved the sensor to the pan and all was good. Could have been a fluke, I don't know, but there was definitely a restriction with that set up I had.

It sounds like the in-line sensor was restricting the flow and it wasn't able to pump enough fluid through causing the overheating. Good thing you caught it and didn't have a fire!

 

[rwill]

Mine is on the drivers side of the pan ,have been told that will give false temp because of internal mechanical heat(pump). I run a radiator cooler and a Derale 10,500lb. fan assisted cooler and cannot hold 200-210 degree temp in summer time Arkansas heat.FYI