I don't know if there's something wrong here or what everyone else's temps look like, but my TFT and EOT are really far apart when coasting on the highway, almost 30° difference. Is this normal or am I running too hot. I've read that both temps should be close but I'm far from that. I took a screenshot today at highway speeds between 60-65mph, not hauling, normal crusing. My oil level is on point, am I worrying too much? It was in the 60s today, brisk weather. 02 f250, 6637, 5" straight pipe, dp tuner, beefed trans billet torque with shift kit. Thanks.

 

My truck runs FAAAAR warmer than yours...

I was at 218*F EOT at 68MPH on the freeway heading home..

TFT was at 165*F

I have never heard they should be relatively close...

Now I'm starting to worry!

 

Your transmission isn't even warmed up. Are you running a big cooler?

 

Temps look ok but the trans slip looks high should be close to 0 when the TC is locked.

 

I believe you may be referring to the Engine Coolant Temperature (ECT) and Engine Oil Temperature (EOT). Not, the Transmission Fluidd Temperature (TFT)

 

I agree they are two completely separate systems (TFT and EOT) with different loads associated with them. My TFT seems to run about 90 degrees above ambient most of the time, this is with the stock cooler and no load except the weight of my big behind and the truck.

 

This was on a 35 min drive back from work on the highway, if I drive 70-80 mph I'll get the trans up to the 165-170° range easy. My EOT I got close to 190° by the time I got home with the city/hwy mix driving. Im trying to look for where I read it was supposed to be close, it was on this site as a matter of fact. I was just worried that my EOT was alot higher then my TFT at the given time. My thoughts were I may have a clogged line somewhere.

 

There is nothing that would make the engine oil and trans temps be anywhere near each other. There is no relationship whatsoever.

 

There you go, if Mark says it, you can put it in the bank! He really knows these transmissions inside and out.

 

I think it's like Pirsch Fire Wagon says - some confusion with ECT vs TFT. Automatics don't have the ECT on the OBDII port, so the whole thing was an exercise of clarification.

Those numbers run very close to what I run when it's not over 80 degrees outside.

Torque Converter slip - this will get a bit technical, but is will alleviate some fears:

• Torque Converter slip is measured by the difference between the Output Speed Sensor (OSS) and the Turbine Speed Sensor (TSS).
• The sampling of each is not instantaneous - they are sampled at different times.
• Any fluctuation in speed that occurs between one sample and the next can show up as a small slip.
• A fast-sampling OBDII gauge will show different results than a slow-sampling OBDII gauge.

My formula in Torque Pro helps to make the Torque Converter Slip read close to AE, FORScan, or other fixed-setting OBDII gauges. The formula is ((A*256)+B)/4.

 

I believe I did confuse ECT with TFT, my fault. This morning I drove about 35 mins into work and took readings once I parked, they're about the same as yesterday so no worries. Thanks all I appreciate the help and info on trans temps along with EOT temps.

 

I figured I would touch on this to clear it up a little since it was mentioned.
TC slip. Yes it should be 0 while locked. Tugly once said something about this. I'll quote as good as I can.... TC slip with low numbers, let's say 0-25 or so is the same as "white noise" and is nothing to worry about. Once you start seeing in the 100s then you have an issue.
I personally had a converter go out without sounding like there was marbles in it. My rpm slippage would shoot well over 1000 rpm and the truck would down shift to 3rd gear on the slightest hills cruising down the expressway

 

Good to know on the TC slippage. I had wondered about it when I first had my gauges but assumed it was normal. I'll be sure to watch for larger numbers.

 

Nope. You've described torque converter slip. Transmission slip is measured by turbine speed (TSS) and output speed (OSS.)

I'd say if you see 20 RPM slip when it should be locked you have a problem. I consider anything under 15 RPM noise. Between 15 and 20 RPM is cause to watch carefully, over 20 RPM is where I think you should find out what's wrong.

 

I checked this on my way home and noticed transmission slip is within a very small amount when in 3rd gear but as soon as I shift into OD the difference becomes huge. Almost double. I assume this is due to gearing?