Transmission Cooler Worth It?

[MrLynn]

How do you measure transmission oil temperature?

Not that it would have helped when my 2013 Ford Expedition's factory oil cooler failed when one of the connections to the radiator came loose:

https://www.escapeforum.org/forums/f...own-24905.html

Fortunately, we were only 30 miles from home, but we were just heading out on a trip. With the Expy in the shop, we cancelled the trip.

But it just occurred to me that I have no idea how to know if my oil cooler is working or not. Unless it disconnects.

[Viajante]

To really know if an auxiliary transmission cooler is worth it you need to have an accurate digital gauge. It seems most vehicles have only a needle gauge that measures engine temperature. Maybe recent trucks are better equipped to give accurate information.

4Runner engines have two transmission heat sensors, one for the hot reading between the transmission and the stock cooler in the radiator, and one in the return line. You need an app like Torque to see the gauges on your phone. You can see how fast the temp rises in a shifting engine and how quickly it cools off. Transmission fluid works hard through the repeated shifting cycles, running both hotter and cooler than the engine temp needle gauge would indicate.

My experience is that an auxiliary transmission cooler did work to keep the fluid temperature down. But, from running my current 4Runner without the auxiliary cooler, the stock cooler located in the radiator has been sufficient on its own.

Another observation is that the highest temps and the least cooling occurred when backing the trailer into a site and jockeying back and forth a few times to get it right. Or inching forward in stalled traffic.

The best way to keep transmission temperature low is to keep the engine from shifting and hunting between gears. This means manually shifting to a lower gear. The revs go up and it seems like the engine is working hard, but the transmission likes it.

[Centex]

Originally Posted by MrLynn

How do you measure transmission oil temperature?

Not that it would have helped when my 2013 Ford Expedition's factory oil cooler failed ....

In the case of your 2013 Expedition it's almost certain that the transmission fluid temp (TFT) is monitored by an OE sensor and is a bit of data which can be extracted via the OBD port. Many other vehicles may lend to the same.

You'll likely find tools for accessing and displaying that data (dongles and smartphone apps, for example) by searching vehicle specific forums.

In the case of my 2005 F150 I'm able to display the TFT using a ScanGauge II

In the case of the 2021+ F150, Ford provides an un-calibrated analog TFT display on some trim levels but a simple FORScan tweak adds display of the numerical sensor value as shown on mine here:

[koakea]

Originally Posted by MrLynn

How do you measure transmission oil temperature?

Not that it would have helped when my 2013 Ford Expedition's factory oil cooler failed when one of the connections to the radiator came loose:

https://www.escapeforum.org/forums/f...own-24905.html

Fortunately, we were only 30 miles from home, but we were just heading out on a trip. With the Expy in the shop, we cancelled the trip.

But it just occurred to me that I have no idea how to know if my oil cooler is working or not. Unless it disconnects.

Not sure about Ford, my Silverado 2018 has it as an option in the menu on my dash. I asked the dealership to set it up at my last service. Now I can toggle to the transmission temp and it gives me a reading. Normal driving the temp ranges between 180 to 185 F.

[Telescopist]

Originally Posted by UncleTim

A description of the I-70 corridor leading up to Eisenhower Tunnel.

The distance is about 26 miles. The grade is severe at times. Idaho Springs elevation is 7,526 feet above sea level. Eisenhower Tunnel is 11,000 feet with a severe increase in grade immediately after Georgetown culminating at the tunnel itself. Remember motors lose horsepower with elevation and 11,000 is very high.

This run is considered one of the benchmark runs for engine performance and tow-ability anywhere. I too have a transmission cooler in my Tundra. I highly recommend them for high stress, high temperature conditions when you are putting abuse on the engine.

We talked to a camp host at the Fruita Campground at Capitol Reef National Park who owns a @2004 Tacoma and 2014 21C. He lives on the outskirts of Denver. Said we shouldn’t have any problems at all making it through the Eisenhower Tunnel. We left Dead Horse Point State Park early one October morning last year and took a stab at it.

I installed an auxiliary tranny cooler soon after I purchased the 4Runner. Our transmission temperature never got higher than 205 during the ascent. I was very pleased with that result. Granted I could have used more horsepower, but I don’t think we fell below 50mph during the final climb.

Factoids: Eastbound Ascent
Base Elevation: 8,795 ft
Summit Elevation: 11,158 ft
Vertical Distance: 2,363 ft
Driving Distance: 8.5 miles
Steepest Reported Grade: 7% for 7 miles
Calculated Average Grade: 5.2% for 8.6 miles

[EscapeBoulder]

We too live in Colorado, and also have an aftermarket tranny cooler in our Highlander tow vehicle. It seems reduce the tranny temperature by as much as 30 degs F. We also have a ScanGauge so I can keep an eye on the tranny temperature. I also use the ScanGauge to confirm what gear the transmission is actually in, as I like to prevent hard shifts of the tranny towing in the mtns, and tend to down shift for downhills, using the engine for some of the braking.

[Kingfish]

I tow my 19 with a 4runner......tranny cooler and ScanGuage added. Been up and down and all over the Rockies. 205 degrees is the hottest I've ever seen, and that was going over Monarch Pass. Kept a nice constant speed of 40mph in second gear.

[Perry Butler]

My transmission will be cooler when running at greater than 2,500 rpms vs 1,500-2,200 rpm in rollers. Many times I'll be at 3,000 rpm's on steep grades, especially in high altitudes. My last two F150's had the Tow Package though.

I did install a tranny cooler on our 2003 Odyssey that was still running perfectly when rust killed it at 280,000 miles, with probably half of them pulling our 16' Scamp or 17' Casita

I never lug the engine. At 62 mph I lock out 10th gear, and at 55-60, 9th gear is locked out. They run perfect at 1,800-2,000 rpms when locked out on the flats. I really wish Ford still offered the 4.11 rear end.

Food for thought,

Perry

[Iowa Dave]

With 4:11 gears you can really get lost
I got safety tubes but I ain’t scared
Brakes are good. Tires fair.

With thanks to to Commander Cody and his lost
Planet Airmen.
Iowa Dave

[Shiny]

Originally Posted by koakea

Mike, Thank you for such a prompt reply. I'm excited to hear how your truck does on your next trip. My son lives just off I-70, in St. Peters, MO, about 40 miles west St. Louis. I think that's where I'll be storing the truck and trailer when we get this plan going.

When you mentioned the back-up camera, are you talking about the camera on the trailer? I'll search for the tread you mentioned and read up on it.

Do you have a cover on your bed? If yes, can you close it with the Andersen hitch in the bed? Sorry for all the questions. I appreciate anything insights you may have.

Aloha, Mike

Highest temp on I-70 was 145. This happened approaching the Eisenhower tunnel when we were crawling and high. Most of the trip with speed over 30 mph was 129 to 135. So far so good and definitely an improvement.

We have a folding cover on the bed and yes, we can close it with the Anderson hitch in place.

[Shiny]

The Mishimoto cooler on our 2018 Silverado along with the change in bypass valve have definitely improved the transmission cooling.

On the trip home, the temperature was never over 150 over Vail Pass and on the eastbound climb up to the Eisenhower Tunnel.

Even better, the low-speed/low-airflow performance is much better. I had to maneuver the trailer to store it. In the past, this could push the temperature to 240 or more. I saw 178 max. Much improved.

Originally Posted by koakea

Not sure about Ford, my Silverado 2018 has it as an option in the menu on my dash. I asked the dealership to set it up at my last service. Now I can toggle to the transmission temp and it gives me a reading. Normal driving the temp ranges between 180 to 185 F.

If you have the dealer perform the bypass valve change recommended by the service bulletin, I predict you'll reduce this by 30 or 40 degrees. When I'm not towing, our truck now typically runs ~130 degrees.

Originally Posted by Telescopist

We talked to a camp host at the Fruita Campground at Capitol Reef National Park who owns a @2004 Tacoma and 2014 21C. He lives on the outskirts of Denver. Said we shouldn’t have any problems at all making it through the Eisenhower Tunnel. We left Dead Horse Point State Park early one October morning last year and took a stab at it.

I installed an auxiliary tranny cooler soon after I purchased the 4Runner. Our transmission temperature never got higher than 205 during the ascent. I was very pleased with that result. Granted I could have used more horsepower, but I don’t think we fell below 50mph during the final climb.

Factoids: Eastbound Ascent
Base Elevation: 8,795 ft
Summit Elevation: 11,158 ft
Vertical Distance: 2,363 ft
Driving Distance: 8.5 miles
Steepest Reported Grade: 7% for 7 miles
Calculated Average Grade: 5.2% for 8.6 miles

Agree that climb is a good test and glad your vehicle handled it well.

I'm still disappointed Chevy would rate our truck to pull over 7000 lbs yet reduced the cooling system cost and performance to the point where pushing our 5.0 around the yard without airflow could heat the transmission to over 240 degrees. Maybe newer trucks are better but at least this design weakness created a market for bolt-on coolers like the Mishimoto we added.

Mike