problem w/ my gen 5

[Mighty~Mart]

Kinda hard to explain but here goes...

Only on extremely cold mornings this happens. I start my car, let it warm up, then head for the highway to go to work. When i'm about to enter the freeway going about 40-45 MPH i feel and hear the engine rev at about 3 RPM. i don't think this is normal since i drive an auto and it usually shifts by then.

My question is should i worry about this? is my transmission messed up? mind you that this only happens when the weather is below zero (celsius)

any help appreciated

[Nick]

if you got your foot down it'll shift at over 5000rpm, i don't think that's a problem, especially for an I4 trying to propel a 3200lb beast up to hwy speeds

[5spd V6 ClrTail]

When the transmission is cold, it usually will take a longer time to reach the overdrive gear. Nothing to worry abou though.

[kgasso]

On my 03 (non VVT-i, 4spd-auto), it's not only for OD (4th or 5th depending on the tranny/year)... it holds gears a little longer from 2nd on up (that I can notice anyway).

[MASTERNC]

I'm having the same issue with 2nd gear and it doesn't depend on the air temperature. If I'm going a constant speed (30-35 MPH) after starting the car the transmission will not shift to 3rd gear until I hit 3000 RPM for at least a second. It's a pain because I don't need all that power and it just wastes gas. Sometimes it'll only do it the first time I use the car in a day and other times it does it again after being off for a few hours.

[BlackCamSe]

Read the manual, the tranny wont shift into OD till' the engine is at normal running temp.

[MASTERNC]

Originally Posted by Camralon2343

Read the manual, the tranny wont shift into OD till' the engine is at normal running temp.

I can buy that, but why won't it shift to 3rd gear? Overdrive is 4th gear.

Why would they do that anyway? I can shift into high gear on a stick shift anytime I want--nobody's ever told me to do otherwise. Running high RPMs just burn gas and I'm trying to improve my already poor gas mileage. I hate racing the engine when I don't have to.

[laphan]

http://www.autoshop101.com/forms/h16.pdf

Look at page 6.

Seems like they program it so it won't upsift to 3rd gear until your engine reach some specified temperature.

[MASTERNC]

OK that tells me that the car is designed to do that.

My question is there any reasoning to set that program? Again, as I said, I can shift a manual transmission whenever I want and I've never had any negative effects regardless of how quickly after start driving after ignition. The manual doesn't say that the same thing is done for 4-cylinder automatics.

If there's no real benefit to it, I'd rather have it turned off (but that seems impossible given what the manual states). Guess I'll have to resort to the old practice of warming up the car before driving (engine will run lower so hopefully it'll mean less gas).

[laphan]

I'm actually an engineer who is working on engines. Toyota program it that way because of emission. Catalytic converter is not going to work right if the temperature is low and also most wear on engines are from cold start (faster warm up, less wear).