"Six of one, half a dozen of the other."
As with most things there is a trade-off when it comes to shift firmness. For modest power levels in a mildly modified vehicle, firmer shifts will ultimately be better for the friction elements (clutches) in the transmission. The less time that the clutches slip during a shift, the longer they will last.
However, most mechanical parts inside the transmission will suffer. These parts are namely one way roller clutches or sprags (which are usually used for 1-2 shifts in most transmissions), friction element drive splines, and the tiny planetary gear sets. Any time there is a near-instant reversal of rotation, near-instant stopping of rotation, or near-instant starting of rotation, the longer the time that these actions can be drawn out, the longer the life of the hard parts. Automatic transmissions function by these principles.
The rest of the drivetrain will remain mostly uneffected by firmer shifts, mostly because there isn't enough time during the shift to "unload" the drive components. The less "on-off-on" power transition time between shifts, the better.
__________________
Tuning, PCM flashing, and burning chips for 7.3s since 2008. Repairing all aspects of 7.3L Powerstrokes for 25 years.
Eight 7.3L PSDs in the driveway including a 1994 Crown Vic and 1973 F100/2002 F350. Looking for the next victim.
|