All shifts are controlled by the computer and are a balance of road speed and engine load/throttle position. If the shift was much earlier the engine would lug. The lock up clutch should come in on light throttle at 45/50 MPH, This can be detected by watching the rev counter. At about 60 MPH lift off throttle and the revs should drop, then put on more throttle and the revs should rise and then drop back as it locks. Maximum economy is with the converter locked, ie in excess of 50 MPH
mags, November 2010
