Engine/Transmission (1998.5 - 2002) trans. temp gage setup advice

[sgf]

After a long time consuming the tons of gauge information out there, I have finally decided to add a 0-35 psi boost, 0-30 psi fuel pressure, and a 100F - 250F transmission temperature gauge to my '01' 3500 dually. I am about to place my order with Genos and I have two choices of how to pick up the temperature. Which of these would you prefer for this application. My only goals are accuracy and reliability?



B&M http://www.genosgarage.com/BM-DRAIN-PLUG/productinfo/BM-80250/



Acu-Temp http://www.genosgarage.com/ACU-TEMP-ADAPTER-89-12/productinfo/ACUTEMP_ADAPTER/

 

[JR]

The acutemp will be much more accurate and will give you a quicker reading. The pan isnt nearly as accurate as it sees fluid that has come out of the cooler. If you plan on keeping your truck stock the 0 to 35 psi gauge is fine if you plan on modding you may want to go with higher readings

 

[Jim W]

I have had both on my 08 Mega Cab. The Acu-temp read about 40 to 60 degs less than the actual output from the transmission.

I tend to disagree with most users who state that they believe the pan temp is not the correct place for a reading. I believe that you should know the input temperature of the oil to the component after the cooler has done its job. If you read the output temperature of the oil going to the cooler and it is reading 250 to 275 F it is too late to save the transmission the oil already has cooked the seals. Now if the oil in the pan is approaching 210 or higher you will have enough warning to shift to another gear and speed the fan up to cool the oil faster or pull over and let the oil cool, thus protecting the seal and such on the transmission.

I also went one step further and installed a Mag-Hytec pan to increase the oil amount and cooling ability of the AL pan. When towing my 5er I normally never go over 180F in the pan when towing even in the Rocky Mountains.

Jim W.

 

[cerberusiam]

If you read the output temperature of the oil going to the cooler and it is reading 250 to 275 F it is too late to save the transmission the oil already has cooked the seals.

This is exactly why reading the fluid temp in the cooler output line is so important. The misconception being that if the temp is high in the cooler output it must be high in the trans. That assumption is false. Given a good transmission, the highest temps and 80-90% of the heat will be generated in the TC during fluid coupling. The path of fluid from the TC is directly to the cooler and the sump. The hot fluid is NOT introduced directly to the transmission components. The cooled fluid is returned to the pan whihc is a mix of existing fluid and hot fluid directly dumped from the TC. The reading in the pan will always lag max temp by a good percentage and is much slower to react to driving conditions. A 180 degree temp in the pan may be a constant 240 degrees at the cooler output.



If you want to drive by the gauge and use pro-actively put the sensor in the cooler output line. If you want a guage to make you feel better you can put the sensor anywhere you want.



Get a 60 ps boost and 320 degree trans temp, you might need them at some point. All that matters is getting used to the normal positions so you quickly tell a porlbem by needle position.

 

[buzzman]

I put the Acu-temp on mine, attached to the line coming out of the trans. Seems very accurate to me. Did some test drives, warmed the trans up, then back in my shop I aimed my infrared temp sensor at the same line and it showed within 4 to 5 degrees of what the gauge was showing.

 

[cerberusiam]

That is because an IR gun is no more accurate than the Accu-temp. Of course they read the same as they have the same variance, 20% or more. The worst problem with the Accu temp is it reacts too slow to be useful. Put the probe in the pan if that is all the accuracy that is wanted.

 

[RClark]

If you really want to know what is going on you need 3 gages, Pan, converter outlet, cooler outlet. Then you can judge what is really going on.
I learned diesels aboard Navy ships and we had gages and thermometers everywhere .

 

[cerberusiam]

Yes, 3 gauges would be optimal. Just not that feasible. In that vein we should have an EGT gauge on every cylinder as close to the port as possible but that is even less feasible.

Monitoring cooler output line temp gives you max temp in all modes, effective cooler efficiency in lockup, and approximate sump temp in lockup. Thats all that is needed to adjust driving style to the situation, more info is just over kill.

 

[RClark]

Three senders can be routed thru a 3 position rotary switch and the switch would feed one gage. Cuts the clutter down.