I think I may have a faulty trans temp gauge. As soon as I start driving right after start-up the trans temp will start climbing immediately. I mean it's around 150-160° within seconds. In heavy traffic it will spike to about 240-250°. I've had several different gauges in the past and never had one to read like this one. Could the sender be bad? I'm pretty sure the initial increase in temps is not normal. With my Isspros or any of the other gauges I have had in the past it would take several minutes for the needle or the display to read more than 100°.

 

My egt gauge does this! Who makes yours?

 

My gauges are all Autometer Cobalts.

 

Even in 90-95 degree is takes alot to even get the trans temp up to 150-160 degrees.

I don't think I have seen it get over 165 degrees.

 

Let the truck sit over night (the longer the better) for this check. Then before the sun has much of a chance to heat everything up turn on the key but do not start the truck and see what the temperature of the trans is. It should read close to ambient just like your intake and cooling system should be reading. If without running the truck you read more then 15 or 20 degrees above ambient then you need to check if the gauge or sender is out of calibration.

FYI - in high temperature areas and idling in stop and go traffic you can easily push 230. Now for those guys that never see high temperatures, I would think the gauge or sender was just as suspect as the guy that always sees high temps.

 

if you have the sender in the hotline you are fine. I can sit in traffic and the the fluid will get to engine temp. It has to with the heat exchange. It only makes sense. Those that never see above 160 almost certainly have their sender in a test port or in the pan. If siiting at a light after some stop and go I get to 210-215 and a few qucik jumps light to light and I will be at 240-250. Once the converter locks it drops rapidly.

 

I have my sensor in the trans hotline. It will climb pretty quick, but you have to remeber that is the hottest fluid. I am wondering what is the best place to pick up fluid temp, the hottest part (fluid that is leaving the trans) or a average of the fluid that is about to get used (pan)

Tobin

 

The sender is located in the hot line and that's exactly what mine does. Stop and go will be around that range and if I stab the throttle a couple times it'll spike up to those temps you mentioned. After the converter locks it drops rapidly. So I guess it's all okay.

By the way I have really just noticed the higher temps the past couple days which have been pretty toasty. Yesterday it was 101° with nearly 100% humidity. Today the heat index is supposed to reach nearly 110°. I'm sure the outside air affects it to a point.

 

Looking at your original post, you say it starts climbing immediately, I had the same issue after the heater core was replaced, the issue was a bad ground to the gauge. Regrounded it and its working fine. It still gets warm with 90 temps here though...

 

you must drive 45 on the highway and never see a red light

 

Again, with the water to oil cooler, the dang trans fluid will get to engine temp. No way around it so those never seeing above 160 are not seeing valid temps.