Not sure the wire colors (used a test light). There is a 12V key active signal to the radio. I used that lead for my source.

Also, if you have the trailer towing package, there is a harness for the brake controller that includes 12v fro instrument lamps.

Tony

 

I've seen that bit about 20 degrees halving the life of the transmission fluid before. There's something I don't understand about that statement though. There is no time factor involved. So if my temp reaches 210 and dwels there for 2 minutes before cooling to to 190 I have lost half the remaining life of the fluid. What if the temp dwels at 210 for 3 hours instead of 2 minutes. Still only half the life lost?

 

You're right Tiger that's a variable that is never taken into consideration so I would assume that It's based on a constant temperature.

 

What's the hottest you guys have seen your fluid get?? I would imagine like mine, it has happened while cruising with the converter unlocked in O/D. My hottest during that condition was about 203. I turned off O/D to see what would happen. It cooled off. Don't know if it would have gotten hotter or not if I had kept going. I'll try it again next time. Other than that, never above 180

 

Tiger / Le Pew,
You are correct....it does take a certain amount of time for the fluid to degrade. The higher the temp, the less time it takes. If your trans was always operating at 210F, then the fluid would last about 25k miles. If your temp oerates at 180 and spikes to 210, then it is likely to last 25k to 50k miles.
It always depends on operating contitions, load, etc.


Galaxy,
I've probably had it a lot hotter, before I installed the gauge. W/ the gauge, it's been to ~200F.

Tony

 

WOooooHoooo, just walked in the door from about a 250 mile road trip. The old tell tale needle actually touched 220. That was going up the mountains at 70mph with the converter locked up but the grade wasn't steep enough to cause a down shift. I left the cruise on and let it do it's thing to see what would happen. After about a minute at 220 it finally downshifted and the temp immediately dropped. Yea baby...Cookin!! Other than that one eppisode, never above 190 all day...highway, traffic, in town, didn't matter. What do you guys think of that??

 

I have a 10 cent bet that Mark Kovalsky works at Ford Transmission in Livonia; and a 5 cent bet he's an engineer.

 

I seem to read some confusion on how the oil travels in the auto tranny of our trucks.

The pump picks up fluid from the pan and uses it to power(main line pressure) the transmission and also sends this fluid into the converter. The fluid leaves the converter and goes through the exit line to the tranny cooler. This oil is the hottest as pointed out by a few ppl.

Obviously the main line pressure is splashed about by moving parts and does some lubrication work too.

The returned fluid from the cooler goes into the lubrication cuircuit of the tranny. The returned oil does two things,,, as it lubes, it also removes heat from the parts. Some folks think the returned & cooled oil is simply dumped back into the tranny pan for re-use.

As pointed out the temp of the oil in the pan is the closest to the "operating temp" of the oil.

I do not consider myself an expert, but I have worked on , with and sometimes against auto trannys since 1974.

 

I don't know if this helps alot but I do know this...The converter is the last thing it does in the trans. Once it leaves the converter, it goes out the cooling lines...out the trans-in the radiator-out the radiator-in the cooler-out the cooler-back to the trans. After that, I don't know.

No one's got any comments about my ~220 temp???

 

in your previous post you mentioned that you have the sensor in the cooler line that comes 'out' from the tranny.

As you seem to know this oil is coming directly out of the converter and in my opinion is the wrong place to have the sensor.

The oil is only 220* for a few seconds till it hits your coolers at the radiator located at the front of the truck.

If you had the sensor in the main case or pan of the tranny and it was running 220 then you would need to cool the fluid off some how.

 

Maybe...But by having it in this line you are reading the hottest fluid in the system. That way you know everything else is cooler than what's on the gauge. This is the 'ideal' place to have it. It would do no good to monitor the coolest temp in the system or even the most moderate temp in the system. There has been some debate over the best location to pick up the temp but the majority is you would want to monitor the hottest fluid, which is what I'm doing. This is true for other things as well, like engine oil. You wouldn't want to take the temp after an oil cooler.(not talking about our trucks here, just generic question) I knew I wanted to monitor the hottest temps and from the majority of the guys in here is why I installed it that way.

 

Galaxy,

I agree with you reasoning for the most part. However, why wouldn't it be a good idea to get a temperature reading that is more indicative of the rest of your transmission. In other words, to get an accurate temperature of the actual tranny, why not install it in the pan. That way, you can get an accurate reading of the oil while it is in the transmission, not after it exits. Just curious as I'm preparing for my installation and my transmission man told me he would mount it in the pan.

 

You know, for the most part I took what I know about engines (oil systems) that I learned from racing (my car is in my gallery link), guys at the track, talking to manufacturers and stuff like that about engine oil and other fluids and tried to apply the same principles to the transmissions. I do not claim to know anything but the bone basics about automatics since my truck is the only thing with one. BUT, I have always been told you want to monitor the hottest fluid in the system. This gives you the best indication of what's going on inside as far as work being performed. Monitoring the hottest part will be the first indications of problems also, where as somewhere else in the system where the fluid is cooler may hide problems not otherwise picked up on. I took these principles along with the majority of recommendations from people in here to install it there. It made sense to me. Look at it this way also, if you are monitoring what you KNOW is the hottest fluid in the system, that's going to give you your best, most apparent indications of problems. Besides, my monitoring it like this, you KNOW that all the rest of the fluid is cooler than what you are monitoring so what does it matter?? Everyone analyzes things differently. I'm also not saying that in the pan is a bad idea at all but I do know it's not the hottest fluid in the system. Here's a senario for ya (hypothetically) Let's say you had a problem with your converter which is the last component before the fluid leaves the trans bound for the coolers. Your fluid would pass through the coolers and may return to a somewhat normal temp before it returned to the trans and showed up on your gauge. Just guessing outloud. I don't thing there's really a bad way, just what ever you've been taught.

 

Want to see a high temp reading? Power brake the tranny in gear with the brakes applied firmly. It will heat up the converter and the fluid coming out of it.

I build transmissions for a living. I test them on a V-8 powered transmission dyno. I can build 250+ degrees in the fluid in 30 seconds from a room temperature starting point. You should see what a 6,000 rpm stall speed converter can do to oil temps...LOL

I build trannys for street vehicles to 1800 horse power alcohol funny cars and monster trucks.

So , yes there is a lot of heat built in the converter. That is why the OE manufacturers send the converter fluid to the cooler immediately.

The exception being the air cooled converters that were used on some of the older cars. Even in the 50's some auto trannys did not have cooling systems on them.

Some of our super high HP trannys we do not run coolers on since they work for 2 minutes or less at a time. These are highly modified power glides with revised oiling circuits in them.