ECT
Q: What does the button on my console labeled "ECT" do?
A: ECT is an abreviation for "Electronically Controlled Transmission". The button has two positions, "POWER" and "NORMAL". When switched to the "POWER" position, the ECM shifts the transmission at higher engine rpm in every gear. It also affects the function of the torque converter lock-up mechanism.
For further discussion see the following thread:
http://www.automotiveforums.com/vbul...8&page=1&pp=15
With regard to the stiffness of the upshifts, in all of the transmissions, as the throttle angle rises, more pressure is built up. This does not change the maximum pressure exerted during the shift, or while in gear. Thus the shift stiffness is unchanged in either ECT mode.
(Thanks to Toysrme for adding the above clarification on shift stiffness.)
OVERDRIVE
Q: What is the function of the overdrive? Is it a separate unit or actually part of my transmission? What happens when I push the button on the side of my shifter and light the "O/D OFF" indicator?
A: The overdrive is the highest (lowest numerically) gear in your transmission, by definition higher geared than 1:1 or direct drive - and it is integral with your transmission. When you push the button on the shifter and light the "O/D OFF" indicator, you prevent your transmission from engaging the O/D gear and it stays in the next highest gear.
Preventing OD from engaging is useful when you are in stop and go traffic and never get above 30 mph for any length of time. Then, the only time you engage the O/D gear is when you let off the accelerator - causing the transmission to make an unnecessary upshift when you are slowing down. It is also useful to disengage the O/D when you are in hilly country or towing and find your transmission is not able to stay in the high gear. It is better to maintain the next highest gear by turning off the O/D than to have the transmission searching for the correct gear.
How an automatic transmission works:
http://auto.howstuffworks.com/automa...ansmission.htm