Petra, being retired from the Allison Transmission Div. Of G.M. we experienced 2 types of shifts above and below the ideal.
There is the positve shift that engages the gear selection firmly. And the soft shift that engages softly and can have 2 different gear components engage at the same time until the governor line pressure is high enough to complete the up-shift.
Ofcourse the second type is the more pleasant of the 2 and that is what most passenger cars have; whereas the first type snaps your neck so to speak and this one is for the industrial transmission.
My shift of choice is the first because the internal components are not in that in between slip mode as are the second type.
The first type will give you longer miles between repairs and the soft shift will not do as well.
Adjustment can be made to get a median between the 2, but if it was mine I would lean toward the harsh, positve shift.
My 1987 W124103 has 174,000 miles and has always had a "Harsh" shift. Other than fluid/filter changes it is still original not even front or rear oil seals.
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Happy Trails Beep Beep from Houston!!!