ECT and Overdrive

[NickP]

When does everyone use the ECT and turn OD on and off? My first SUV, so I have not figured out the way the Trans works.

 

[regularguy412]

When ECT is 'on' , the transmission computer delays the 1-2 shift and the 2-3 shift (providing the engine is under light or moderate load ). With the ECT 'off', the transmission computer shifts to 2nd gear and 3rd gear , sooner -- presumably to lower engine RPM and enhance fuel mileage. All of this is still dependent upon throttle position and just how hard you are trying to accelerate. If you have your foot on the floor, the transmission will stay in each gear the maximum amount of time,, until a certain speed / RPM is reached, regardless of whether the ECT is 'off' or 'on'.

When the O/D switch is 'off',, it effectively locks the transmission out and prevents it from going into overdrive. With the O/D switch 'on', the transmission will shift into overdrive above approximately 30 mph. This is still dependent upon how much load the engine is under. Overdrive will not kick in until the engine senses it is 'cruising' and not accelerating. You should also note that even if the O/D switch is 'on', the transmission will not kick into overdrive until the transmission has reached appropriate operating temp.

Around town, I generally have the ECT 'on' and the O/D 'off'. It seems to make the 3.0 more driveable with 31 x 10.50 tires. On the highway when I will be cruising at more than 45 - 50 mph, I usually have the O/D 'on' and the ECT 'off'. When towing, I generally have the O/D 'off' and the ECT 'on', even when traveling at highway speeds.

Mike in AR

 

[NickP]

Thanks,

That helps out alot, I'll give that a try. Maybe you can help me out with this queston, When I start to accelerate passed 50MPH the RPM rev up and it takes a minute before the truck shifts into the next gear, but it kicks when it shifts? Thanks Alot. Nick

 

[regularguy412]

OK. Lemme see if I understand correctly. You are cruising at, say, 55 mph. You floor it to pass another vehicle. The tranny kicks down to 'passing gear' and the engine winds out to about 70 mph. With your foot still on the floor, the tranny then up-shifts to top gear. RPM's drop back to say,, 3500 or so. However, when the tranny makes the upshift to top gear and the R's drop,, you get a hard shift at that point. Right?

Now, what I have noticed in my 4Runner, is that -- if I have the O/D 'on' and hit passing gear , for example when climbing a hill, and I top the hill and let off the gas ,, sometimes the tranny will go straight from passing gear to overdrive and it will be kind of a 'solid' shift. This may be what you are feeling. This scenario also seems to happen when I have the cruise control set and a hill-climb occurs.

You can try staying 'in' the throttle or not just letting all the way off suddenly, and see what happens.

Mike in AR

 

[NickP]

Thanks for the info.

 

[genlrony]

I use ECT when Im getting onto the freeway and then use OD once Im there.

 

[daveboats]

ect problems

I think i have an ect problem. The Trans want shift on its own. You have to shift manualy. I unplugged the ect and it would drive (not great) in D. anybody have such an event or can help please

Thanks Dave

 

[90toytruck.]

i leave my o/d on all the time i seem to get better mileage that way . i only use the ect when towing something .