TERRY R. - Yes, keeping trailer & load to around loaded tractor weight is safer, but paying heed to ground conditions, traction, etc. is still necessary...that's why I posted the approx. weights of the FARMALL M & wagon I was pulling that slid down the hill.
Normal operation hauling in corn, oats, hay etc. on the farm was a 5000# tractor pulling up to a 10,000# wagon. When Dad upgraded wagons I had to drop a gear on some hills with the Super H. With the smaller wagon I could pull any hill in 4th, about 6-1/2 mph, but with the BIG wagon 3rd gear (5 mph) was all the load it could handle. My Buddy hauled corn away from a combine this fall, think He was using a 7810 JD FWA and a grain cart with well over 800 bushel capacity. He ran out of traction on wet ground a couple times. 800 bu. of wet corn is over 50,000# plus the weight of the cart. I noticed the farmers around home with similar sized tractors & grain carts never ran WFO with loaded carts this fall, but when empty were making time!
The dump cart I use on my 982 has a 3000# gross capacity and I know I've at least approached if not exceeded it a couple times. My 982 with weights & 50C deck must weigh 900-1000#. That cart weighs about 600# empty, and it would be NO problem pulling it with the 70 with it's tired old K181, even with a big load of brush or ???? on, but without hydraulics to dump the cart it wouldn't make sense.