pishta

In traffic with the lightest pedal pressure the car changed gear like a motorcycle, no modulation with engine load. Itll bump your head back to the headrest. Under WOT, it shifts great, but it seems to shift the same when Im just putting in stop and go traffic. Is this a transmission servo issue (read up on them and I dont know if they go bad and still work, or just die and the car never shifts?) Ive driven plenty of A/T cars like my 92 LS400 and even my 2002 Siverado service truck and both shift butter smooth in all load conditions. I have used both power and economy modes and there seems to be no change. PWR ECT mode does show in dash so I believe the switch is working. I keep it on ECON.