Transmission Temp?

While I certainly believe hotter trans temps will means shorter trans fluid life, I don't give much credibility to the chart linked above. That company is trying to sell you a transmission cooler, so they are trying to show with 'hard facts' how much you need their product.

I have an F250, so this may not be apples to apples, but my non-towing trans temp is 200F. Towing our 8,500 loaded TT the temperature goes up to maybe 210-215F, even up 6% grades.

I'm curious what temp you are seeing. The highest I have ever seen is 214°. That was on a long slightly elevated climb on a hot Texas summer day.
Mine usually runs between 202 and 210.

The measurement is displayed on a digital display and does respond to activity. It is generated by the same transducer the scan guage reads. How accurate it is I don't know.

Sport45 wrote:
I wouldn't expect the gauge Ford put in the dash to be anywhere near accurate.

X2. Ford is notorious for turning gauges into glorified "idiot lights" by using resistors to peg them in the middle over 90% of their supposed range. This keeps customers from complaining that something's wrong with their cars just because the gauges don't all have their needles in the middle.

Our Class C has the 6.8L V-10 and I have added a Scan Gauge, specifically for trans fluid temperature (among the many other wonderful things the SC does). You can make great use of and control your trans temp by engaging the Tow/Haul mode. Even on seemingly low grades the trans temp will creep up even though the transmission is not hunting. As you notice the temp climbing lock in Tow/Haul and the temp will immediately start to drop, usually 6 to 10 degrees as the transmission becomes more efficient/provides greater cooling. If your rig does not have Tow/Haul mode simply locking out O/D will do much the same thing.

Works for me.

:C

I've found that on my rig the trans temp will nearly always be 100* above ambient temp.

You can run the transmission as hot as 220F all day long with no problem. You can go as high as 250F for no more than a half hour at a time.

Those charts that show fluid live vs. temperature may have been accurate with 1960's ATF, but is WAY off with modern fluids. Trans fluid WILL NOT fail in 50 miles at 300F. I have tested that and proved that it is not correct.

I wouldn't expect the gauge Ford put in the dash to be anywhere near accurate.

nomad297 wrote:

Golden_HVAC wrote:
300F and the transmission fluid is rated to last about 50 miles.

275 and it is good for something like 2000 miles.

Below 230 is what you are looking for, that is good for the normal 15,000 mile service life. When you start to reach 230, it is time to slow down a bit. Perhaps shift into a lower gear, the transmission will pump faster through the coolers, and the fan will speed up, cooling the engine a lot more.

215 is normal range while not towing or climbing hills. 190 is also great temperature. 180 is about the minimum that you want to run on a regular basis. Something like 160 will not be warm enough to boil out any condensation in the fluid, leading to the need to keep it at 180F.

In the winter, you might not see it reach 160F on the short drive to work, so it might be wise to drive it a bit further once a week or at least once a month to warm it beyond 180F for about 15 minutes to drive out any excess moisture.

Fred.

Golden, thank you for all of that information. I have always wondered the same thing. Where did you learn this?

Bruce

Chart in a transmission shop. I think they where pushing you to purchase a auxiliary transmission cooler. The chart might have been produced by Hayden, the transmission cooler manufacture.

You can google just about anything! Found it. Well not that poster, but this link.

http://www.haydenauto.com/upload/HaydenAuto/Documents/Cat_Hayden/2007-hayden-trans-oil-coolers.pdf

So what type of oil cooler is better? The "Stacked Plate" will offer a lower pressure drop than a copper tube type cooler. Staked Plate would be the 600 series, such as model #667 or #668. Copper tube cooler offers a much longer path the oil must take from the inlet to the outlet, such as model #479, that has about 10' of tubing from beginning to end.

Look at the pictures on the PDF above, and you can see the difference. The stacked plate, there is a left and right (inlet and outlet) only about 12" apart. Each plate allows some of the oil to cool as it moves from the right to the left outlet, because there are several plates (depending on the model) the fluid will travel slowly, with very little pressure drop, and cool a lot in the process.

They also sell a stacked plate with fan. This is helpful say if you have a 90's diesel truck, while parking a trailer, and the vehicle is moving very slowly. The engine fan is only turning about 700 RPM, barely any air flow across the transmission cooler. However the transmission oil is going over 230F at the time! Backing into a site, or pulling onto blocks at low speed can damage a transmission - as well as overheating it. Turning on the fan can help in slow speed situations. Over 40 MPH, and the air going into the front of the truck is already nearly 100 feet per second, so the fan is basically useless at that point.

Fred.

Golden_HVAC wrote:
300F and the transmission fluid is rated to last about 50 miles.

275 and it is good for something like 2000 miles.

Below 230 is what you are looking for, that is good for the normal 15,000 mile service life. When you start to reach 230, it is time to slow down a bit. Perhaps shift into a lower gear, the transmission will pump faster through the coolers, and the fan will speed up, cooling the engine a lot more.

215 is normal range while not towing or climbing hills. 190 is also great temperature. 180 is about the minimum that you want to run on a regular basis. Something like 160 will not be warm enough to boil out any condensation in the fluid, leading to the need to keep it at 180F.

In the winter, you might not see it reach 160F on the short drive to work, so it might be wise to drive it a bit further once a week or at least once a month to warm it beyond 180F for about 15 minutes to drive out any excess moisture.

Fred.

Golden, thank you for all of that information. I have always wondered the same thing. Where did you learn this?

Bruce

300F and the transmission fluid is rated to last about 50 miles.

275 and it is good for something like 2000 miles.

Below 230 is what you are looking for, that is good for the normal 15,000 mile service life. When you start to reach 230, it is time to slow down a bit. Perhaps shift into a lower gear, the transmission will pump faster through the coolers, and the fan will speed up, cooling the engine a lot more.

215 is normal range while not towing or climbing hills. 190 is also great temperature. 180 is about the minimum that you want to run on a regular basis. Something like 160 will not be warm enough to boil out any condensation in the fluid, leading to the need to keep it at 180F.

In the winter, you might not see it reach 160F on the short drive to work, so it might be wise to drive it a bit further once a week or at least once a month to warm it beyond 180F for about 15 minutes to drive out any excess moisture.

Fred.