I've personally had two sector shafts twist in my hdj81, and I am not typically hard on my vehicles.
One was after a slow speed slide off a clay forestry road that become super slick after a 20 minute down pour, and I slid into a ditch.
5 cars slid of the same 300 yard stretch of road in the space of 10 minutes.
My slide popped a tire bead and twisted the sector shaft.
I eventually replaced the steering box at 2am Saturday morning before a weekend wheeling trip.
About 2 pm the same Saturday, I hit a small wash out on a forestry road at maybe 30mph abd twisted the sector shaft in the replacement box about the same amount


I was one of 8 vehicles that went through the same washout at about the same speed. Mine was just unlucky.
Both mine, the 1/4" of spline visible above the Pittman arm was visibly deformed.
With the Pittman off mine, the spline within the Pittman was straight, the top 1/4 was deformed by about 10⁰ like the red sketch on the OPs pic below.
Deformation on mine was about the width of a full spline, and resulted in the steering wheel being about 70⁰ on the piss.
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