Don't see any drawbacks for the torque reduction, might be less power or slower if racing but might keep trans from slipping. Not sure how it would interact with the shift firmness tables.
On the 1-2 shift oncoming the y axis shows negative numbers on top two values; the 3-4 shift oncoming y axis numbers are different but might be just mapped or scaled differently. The increased line pressure on the first two numbers of the y axis on the 1-2 shift oncoming chart might be for when there is engine braking going on, could be the same for the 3-4 shift.
TNutcher
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