I have recently returned from a 7000 mile trip with my 2010 Yukon, with the 5.3L, 6 speed transmission. The vehicle also has the GM towing package with the trans and engine oil cooler.
My trailer is about 5000 lbs. I towed from Pittsburgh, PA to Yellowstone, then to Utah and back home. It was in the peak of summer and temps were regularly in the 100 deg F range.
I was mostly worried about the transmission temperature, since the is the primary driver of transmission life. In general, my Yukon transmission temperature runs about 80 deg above the ambient outside air temp. for example, if it's 80 deg outside, the trans temp will be about 160 deg (80 +80). When towing 5000 lbs on flat roads, the trans temp is about 100 deg above ambient (if it's 80 outside, the trans temp while towing is 180 deg). Going up extended low grade hills have little impact, or in a rolling terrain there is little impact to transmission temp. Climbing extended high grade hills, in the 6-7% range, like you will routinely find around Denver, can be result in another 20-40 degrees on top of the 100 degrees already there. So when going up steep grades, assume as much as 140 degrees above ambient.
When I was towing, it was 100 degrees on a regular basis and the trans temp saw 230 deg more than a few times, and 240 a couple of times. Usually around 225 or so, I would turn on the heater to help cool the engine down (that made me popular with the family). Cooling the engine down also cools the radiator, which is were the trans fluid is also cooled. It clearly helped when I did this. Towing in stop and go traffic resulted in about a 120 deg rise above ambient.
I was typically going 65 MPG, but on some of the extended 6% grade inclines, I would slow down as low as 40 MPH, and it was still hot. A couple of times I pulled over and let it idle until the trans was around 210-215. At an idle without air going over the radiator, it would have taken hours to go lower.
Except for the Rocky mountains, it towed fantastic. Even in the Rockies, I had alot of company on the side of the road. There were lots of people pulling over who were towing. Towing in 100 deg temps in the mountains is challenging for most vehicles.
My 2 cents-
Dale
My trailer is about 5000 lbs. I towed from Pittsburgh, PA to Yellowstone, then to Utah and back home. It was in the peak of summer and temps were regularly in the 100 deg F range.
I was mostly worried about the transmission temperature, since the is the primary driver of transmission life. In general, my Yukon transmission temperature runs about 80 deg above the ambient outside air temp. for example, if it's 80 deg outside, the trans temp will be about 160 deg (80 +80). When towing 5000 lbs on flat roads, the trans temp is about 100 deg above ambient (if it's 80 outside, the trans temp while towing is 180 deg). Going up extended low grade hills have little impact, or in a rolling terrain there is little impact to transmission temp. Climbing extended high grade hills, in the 6-7% range, like you will routinely find around Denver, can be result in another 20-40 degrees on top of the 100 degrees already there. So when going up steep grades, assume as much as 140 degrees above ambient.
When I was towing, it was 100 degrees on a regular basis and the trans temp saw 230 deg more than a few times, and 240 a couple of times. Usually around 225 or so, I would turn on the heater to help cool the engine down (that made me popular with the family). Cooling the engine down also cools the radiator, which is were the trans fluid is also cooled. It clearly helped when I did this. Towing in stop and go traffic resulted in about a 120 deg rise above ambient.
I was typically going 65 MPG, but on some of the extended 6% grade inclines, I would slow down as low as 40 MPH, and it was still hot. A couple of times I pulled over and let it idle until the trans was around 210-215. At an idle without air going over the radiator, it would have taken hours to go lower.
Except for the Rocky mountains, it towed fantastic. Even in the Rockies, I had alot of company on the side of the road. There were lots of people pulling over who were towing. Towing in 100 deg temps in the mountains is challenging for most vehicles.
My 2 cents-
Dale
