All a tranny does is manage the engine power/speed so that it is appropriate for the current wheel speed. When the engine gets going too fast in one gear, the tranny shifts to the next gear up so the engine can go slower. The engine produces more torque (rotational force) at lower RPM than at high RPM (generally), hence the lunge when upshifting. What you're feeling is not necessarily the tranny, but all the ancillary bits that comprise the drivetrain. On a stick shift, you can ease in the clutch or drop it in all at once, with noticeable effects on how the car reacts to the difference in force applied. Having the throttle going full bore as the tranny shifts is like dumping the clutch; you may not hurt the tranny, but all the other stuff--CV joints, engine/tranny mounts, bushings, etc., get torqued pretty good in the process. The lunge will likely become more noticeable over time as the bushings in the mounts wear out and the tranny has more room to move when it absorbs the higher torque of the new gear. I'm with Moregolf--ease up on the gas before the upshift, you will extend the life of all your drivetrain components, not just the tranny. It's just not as much fun.