boxster engine cuts off at low speed. wont restart immediately. after 2 to 3 hours, will start up

I can hear a rub sound when making sharp turn and was told I need to change rear end fluids/seals.. The car only has 8,400 miles..

Will reverse slowly on level, but typically moves only after low range is engaged. Fluid/filter changed recently.

I put 6 but still low and going slow now but reverse fine and fluid drain from coolant line

I put 6 quarts in she drive but I have to gun it in drive but reverse work fine