Torque converter lockup
 

I noticed that even though the temp gauge is reading normal; it appears the torque converter doesn't lock up untill about 3-5 minutes of cruising down the highway. When I go to work, I drive about 1/2 mile to the entrance ramp. I notice when crusing about 65mph I am at appx 2400 RPM. After a few minutes it will relax to about 2100-2150 rpm.

Is this normal?

hows ur tranny fluid condition, is it burned? is it low?

don't think so. I did a drain and refill about a year ago. I am thinking that maybe it isn't locking up right away because the temp of the tranny fluid? I am thinking that the temp gauge in the dash isn't very accurate either. I notice it take a while to get to a quarter then in a matter of a few seconds it goes from a quarter to normal. I am thinking that maybe since it is only about a 1/2 mile drive to the entrance ramp the tranny fluid is still not at norm temp and the computer is preventing lockup?

is this at the beginning of the drive? the lockup is based on tranny temp, not engine temp. so the tranny fluid might not be up to full temp until a few minutes after the engine is.

since i have an external cooler on my max. i can say the q45 does about the same thing though.

plus if i can remember the trans. temp. sensor is on the top at the valvebody, or in the valve body.
and the fluid is at the bottom.

Yes it is. I was thinking this was due to trans fluid temp. I am guessing this is normal to help wear and shifting on the trans since the fluid is probably still cool.

or it might be to help warm the fluid up faster. the torque converter creates some heat by the nature of how it works... having it locked up means that heat is not being produced so the fluid could take longer to heat up...... just a thought. not based on hard fact.

my maxima does the same thing.

when the car is cold, it doesn't go into 4th gear until i reach 60kph, it'll just stay in 3rd gear while i'm travelling at a constant 55kph, which is annoying because the speed limit it 50kph so i have to accelerate up to 60kph to get it into 4th and then slow down a bit.

once the car is warmed up, it goes into 4th at 45kph and full torque converter lockup happens at 75kph, but that won't happen till the tranny is nice and warm

Yes This is A normal thing, Im assuming that it happens in order for the engine/transmission to get to operating temperature very quickly. I think I read that in the owners manual or somewhere.