Transmission gauge question

[AllThumbs]

I'm going to put in a transmission temp guage (I think they should be standard equipment) and I'm having a hard time understanding their recommended location for the sensor.

I'm suppose to cut the lower line to the transmission (return line from the transmission cooler) and insert the sensor there. Why? It would make more sense to me to put it in on the line coming directly out of the transmission before it has run through the cooler so you know what the temp is immediately out the the transmission. Anybody know why they do it that way. I even called the manufacturer to be sure and they confirmed that as their recommendation installation.

[trbankii]

I'd have asked for their reasoning when I talked to them.

My only thought is that the fluid is certainly going to be heating up in the transmission and that the question is whether the fluid is being cooled back down reasonably before entering the transmission again.

[bobt]

When I put a trans temp gauge in my '93, I put sensors on both the outgoing and return lines at the transmission and routed the wiring thru a rocker switch so i could see both temps. Was interesting to see the difference between what went out and what came back.
Bob

[93GMCSierra]

I imagine every company uses different ways, the gauge I put in I drilled the pan and put the gauge there.

[AllThumbs]

Their suggested location (according to them) gave you a picture of the health of the transmission cooling system. Let you know that your cooler was working. I still didn't completely understand the answer. I like bobt's answer and will consider it. I think that would be useful information.

bobt, how much difference is there in temps and is one telling you more important information that the other?

[bobt]

It has been a while, but it seems to me that under normal interstate driving with my 4000# Lance camper and towing a Jeep Wrangler, the difference was somewhere in the range of 20 to 40 degrees. Where I mainly used it was when I was pulling a hill and not in overdrive (unlocked torque converter) and the trans temps started to climb rather quickly. The temp of the fluid coming out of the torque converter would get hot rather quickly, but the return temps would be quite acceptable ( could see 220 or higher outgoing, but the return temp might be only 170 to 180 which was comforting). I used to drain the pan every spring and replace with new (I averaged about 5000 mile per year). The fluid I drained out always looked as good as the new I put in.
Bob

[AllThumbs]

Thanks bobt, that is information anyone can use. I'm pulling a 24' 5th wheel with a 16' boat behind it. Your information is exactly what I was looking for.