97 F350 RC 4X4 7.3L PSD E4OD 117Kmi.

Ok, 3rd temp guage ive installed just to make sure, and this one still reads 210 after about 20 min of in-town driving. Prev owner installed sensor in the tranny line coming from cooler to transmission (go-figure?). Anyways, it jumps to 200+ when in 1st, 2nd, 3rd, but cools way down (180) when overdrive kicks in. Sounds like the TC is super heating it to me.

BTW - changed trans oil 4 times in last two months, and it isnt burnt up, and the transmission doesnt shift any different than it did w/60k mi.

 

So you are reading the temp pre cooler?

I would move the sensor to the pressure test point on the transmission.

 

Sounds like the trans and torque converter are perfectly normal to me.

This is why I recommend putting the sensor in the test port. People get WAY too excited when they see the temperatures in the line to the cooler. It's normal, and the only way to avoid getting to those temps is to leave the engine off and the truck in the driveway.

 

your going to get high temps ou of the cooler lines cause of fluid sheer in the tranny, put in the test port on the side of the tranny like mentioned then come back and see what happenes.

180 with torque locked up down the highway is alright meaning the temp is not burn up temp but put it in the test port, after you read the tem with it going through your coolers my tranny temp in test port is 170 highway on a 35 C day, 155 on a 20 C day, pulling 7000lbs and laying into it hard in the city(pulling away from traffic at redlights) I was only hitting 180 at 20C. I also have a huge *** cooler for the tranny.

But be forwarned, if you are tugging someone like stuck in mud, in the test port thier is a delay before hot oil will get to the sender unit. I didnt do damage to my tranny, just heated and blew out oil from my torque converter seal and walked the bushing forward, but my flexplate was also bent, my temp touched 210 at test port so I may have hit 250 I figure coming out of the line to my coolers.

I changed my trans oil the day and installed a new seal and bushing

I like taking temps at the test port cause thats the consistent temp, trans oil does not burn up from have these little temp spikes after its been through your cooler, its your consistent trans temp I like to take, when they say every 10F cuts ATF oil life by half, thats ATF oil running at that temp consistently through its life span. So if your oil is at 190 or lets say 210 all day long, then yeah, I would recommend doing lots of tranny changes. what can I say about your tranny. You have one clean transmission.

 

I understand that an average temp reading is what i want, what i was saying, however, is that the previous owner installed the sensor on the line that flows oil from the cooler to the transmission, the line that carries the oil after it has been cooled - to the transmission. Therefore the oil should be the coolest at this point, not the hottest. And the temp should def. not be reading 210. Is this right? or am I missing something. . .

BTW - i have been wanting to (and will) move the sending unit to the test port, that is where i have always installed it in prev. trucks. A chance that the sending unit is bad??

 

210 degrees on the return line is way too hot. IMO

My in-truck sender in the test port. This will be the hottest reading.

It reads 175 (In truck and infrared), the oil line from the trans to the cooler reads 168 (infrared) the line from the cooler back to the tranny reads 156 (infrared).

My infrared heat gun is very acurate. It took less than 10 secounds to get all of the temps.

 

Wrong. Right in park, but way wrong when the truck is driving.

At idle in park there is zero heat generated in the torque converter, so the line to the cooler will be cool. As you saw it can easily be cooler than the test port.

When the truck is driven the cooler line will be A LOT hotter than the test port, in the right conditions.

 

That sounds right Casey.

I was also going to mention that i do have a Snapon Infrared heat gun, and, yesterday i pulled in the driveway with the guage reading 210, climbed under the truck, and shot the side of the tranny case (170), the bottom of the tranny pan (158), and the cooler lines (175, 155). This made me wonder about my guage, though. why would the guage not drop back down after i put it in park? with the truck running in the driveway, the guage was reading 210, but my heat gun was saying 165-170 right at the sending unit. Is there that much lag in the time it takes for the guage to cool down? (Autometer guages)

 

Worry less, wrench more. Move the sending unit!

 

Casey, So when you put the truck in park the fluid stops moving through lines to the cooler???

All my measurements were taken as fast as you can get out of the truck and shoot those temps I mentioned above.

 

Depends really how hard you were driving it, think, lets say you pull away from a red light, you pass 4 liters(guessing, dont know flow rate) of oil through cooler until you hit lock up. with the oil already worked you could hit lets say 230, after cooled its dropped to 210, enters your transmission housing and mixes with the other 18 liters of oil in the transmission. The transmission itself dissapates alot of heat on itself soooo.........

In the winter time I have my aux. tranny cooler totally covered up and at -20C it hardly ever breaks off 110

 

Agree with him, hot tranny fluid in the torque converter is not as critical as hot oil the rest of transmission.

Itstead of the debate, move the sender into the transmission, check your temp, if your temp is running at 190 like mine did once while on the highway empty then I would look for a restriction in the lines, tranny cooler to small or even tranny cooler bypassed by-passed. My problem was an uncompatible o-ring and it swelled up.

Also, since the previous owner was playing around in their, check to make sure the lines are routed from transmission--->rad cooler--->aux.(air) cooler then back to transmission.

Ummm, I will note I also had a tugger kit installed on my tranny with springs and selinoids, I dont know what he did to it but my trans. temps did jump 10 degrees hotter with this kit, I just installed a bigger Aux trans cooler and have not yet seen it break over 180 with a load.

 

thanks for your replies, i think i got a pretty good handle on it now, im gonna move the sending unit, hope for the best, and just wait till it blows up so i can get a new BTS Trans!

 

Let us know what temps you pull from the test port

 

yea i just switched it to the test port tonight, ill report tomorrow.