Well, Rav4WD, you are correct about TQ converters not locking up until the final gear...and at a certain RPM. I say certain RPM because this varies by engine, tranny and final drive (diff) gearing. I can tell you that once the converter locks at say 2k rpms in 5th gear on the V6 tranny, there is no added efficiency of increasing the rpms to the 3-4k as you mention.Rav4WD said:IIRC.. the torque converters in most of the automatic gear boxes don't lock up until they've reached top gear (4th gear in the Rav4 4cyl and 5th gear in the V6).RAV4Don said:Well, maybe. It all depends on when the TQ converter "locks-up". This maybe in (V6) fifth gear at 2k rpms.Rav4WD said:The torque converter is more efficient at the higher RPM's. If you ram it and drive at 3-4000rpm, there's less power loss thru the torque converter than if you were to baby it at 1-2000rpm.
I wouldn't baby the car until the torque converter has locked up and that would be cruising speed on the highway.