Automatic transmissions have shit torque out of the box
Absolute nonsense, the torque converter multiplies torque at low speed, so an automatic with the same gear ratios as a manual will have far more pulling power than a manual.
And a trans cooler is standard on pretty much any automatic vehicle.
I have driven a van with a cargo barrier, it was rated for 90KG. Do you know how heavy an ATV is? More than that.
The lashing points would also tear out in a big enough impact.
You're talking shit.