The firmness of the shift is not just the transmission or the servo’s, but the setting of the “Force Motor Tables” in the ECM. You can make any shift as soft or as hard as you want with pressure.
If you know someone that can edit the OBD-2 computer, spend some time on the tranny pressure settings. (force motor)
Every time I install a new transmission, the first thing I do is to take my transmission guy for a ride. He drives and watches the transmission pressure and I make the changes to the computer as he calls them out. We adjust the trans pressure from idle to WOT in each gear. Tables are most often pretty close so it just takes a little tweaking.
Pressures will run from around 70 psi at idle to over 300 psi, depending on the pump. One of the tricks to making these 4L60, tranny’s last longer behind large power, is to squeeze the ¾ clutch pack tighter than stock to keep them from slipping.
Seems like most guys around the forum here want the trans to shift hard. I would suggest that you set up the “performance switch” and program the computer to increase pressure by 40%. That way, you can have a smooth shifting trans for day to day driving and whenever you feel the need to jerk your neck, throw the switch.
You should also know that a stock OBD-2 is trying to soften the shift with the torque control. They also lock up the TC gradually to make everything smoother, rather than just going to 100% lockup.
I always recommend going to a stand alone TCU for the tranny. It’s always a money issue for most. Reality is, you will save money in the long run, by buying fewer transmissions.
