I towed everything I owned back in 2013 from Arizona to Idaho when I got divorced. I had a `97 1500 Suburban lifted with 33" tires and 3.42:1 gears and a pro-built 4L60E.
I took my flat-bed trailer and converted it to a redneck covered trailer and loaded it full of the stuff my nasty red-headed ex-wife didn't take (but I'm not bitter...).
I towed it approximately 1500 miles during the summer in temps from 108 degree to 45 degrees. And my radiator had a hole in it that I couldn't afford to fix before the trip, so it could only be filled 3/4 of the way.
Trailer weight was around 7800lbs and the whole thing was just over 13,000lbs on the scales.
It pulled beautifully and I kept it at 60mph or less. Not a single breakdown.
But... The rear-end developed a nasty whine around Southern Idaho. Was just too much weight for too long for that poor 10-bolt...
In the middle of nowhere, Nevada...