08 TR4 V6, Any simple way to stop trans from dwn shifting too quick?

[Spaceman]

My trans down shifts almost every time I go over a freeway overpass. There's lots of them so this is a real nuisance. Extra wear on the trans plus extra gas. This started of course after changing to bigger tires. I would like to tweak something only slightly to stop this.

Does anyone know how to do this.
Thanks

 

[Spaceman]

My trans down shifts almost every time I go over a freeway overpass. There's lots of them so this is a real nuisance. Extra wear on the trans plus extra gas. This started of course after changing to bigger tires. I would like to tweak something only slightly to stop this.

Does anyone know how to do this.
Thanks

WOW...... No response???

Does anyone know how to tweek the trans linkage on this car to accomplish this. I have done this many times on older cars but not sure about this one, with all the fly-by-wire now days.

Maybe someone can anyone refer me to someone that might be able to help?

 

[Acidmeld]

There is no trans linkage. Its entirely ecu controlled.

 

[M1911]

What do you mean that it downshifts when going over an overpass? Does it downshift when you are going downhill, and you step on the brake? If that is what you are talking about, that is called grade-logic and I know of no way to change it.

 

[CJ3Flyr]

Try pulling the engine and trans fuse from the underhood fuse block. Let it 'learn', from a blank slate, your setup. That should help but not relieve it 100%.


Initially make a special effort to be slow with throttle application to 'teach it' you prefer converter-locked, no downshift. After several miles you discover you can, slowly, add quite a bit of throttle without it downshifting and/or unlocking the converter.

 

[Tooltime19]

Weclome to the world of trade offs...Like the rest of us here, you changed to a larger tire size. When that happens, you effectively changed your gear ratio and power band. The best way to fix this issue is to re-gear the truck to accomodate the larger tires, but that gets pricey in a hurry. So, like the reat of us here again, we just shift down from 4th to 3rd on hills like that, then back to 4th again manually as needed. If you shift it manually, you have control of the shifts and power, therefore keeping the computer from downshifting and upshifting too much. By performing this method, you could potentially keep transmission temps down as well. Hope this helps.:biggrin2:

 

[Burt]

What do you mean that it downshifts when going over an overpass? Does it downshift when you are going downhill, and you step on the brake? If that is what you are talking about, that is called grade-logic and I know of no way to change it.

Hey, I really like that grade-logic thing. I go up and down an 8% grade everyday during my work commute and it really holds me at speed with no need for braking.

 

[Spaceman]

Try pulling the engine and trans fuse from the underhood fuse block. Let it 'learn', from a blank slate, your setup. That should help but not relieve it 100%.


Initially make a special effort to be slow with throttle application to 'teach it' you prefer converter-locked, no downshift. After several miles you discover you can, slowly, add quite a bit of throttle without it downshifting and/or unlocking the converter.

Thanks
Very interesting...
I will give it a try. Hope it helps some.

Otherwise........Looks like there is no easy answer!!!
Thanks everyone!!

 

[charlier180]

Hey, I really like that grade-logic thing. I go up and down an 8% grade everyday during my work commute and it really holds me at speed with no need for braking.

:iagree: It also comes in handy when towing and one goes up/down those 7-8%+ grades.

 

[liqourish]

get the apr x-one chip and retune ur ecu to have it ur way.... not worth the 1400 unless yer doin some serious performance upgrades

 

[Spaceman]

Weclome to the world of trade offs...Like the rest of us here, you changed to a larger tire size. When that happens, you effectively changed your gear ratio and power band. The best way to fix this issue is to re-gear the truck to accomodate the larger tires, but that gets pricey in a hurry. So, like the reat of us here again, we just shift down from 4th to 3rd on hills like that, then back to 4th again manually as needed. If you shift it manually, you have control of the shifts and power, therefore keeping the computer from downshifting and upshifting too much. By performing this method, you could potentially keep transmission temps down as well. Hope this helps.:biggrin2:

Getting a little off track here. Please note in my original, I am talking about regular, everyday, freeway overpasses....... Not mountains.
Thanks. No one wants to shift at every freeway overpass... Nor do we want it to auto downshift at each one of the hundreds of overpasses......

 

[chitown40]

Are you talking downshifts while using the cruise control? Or just with the pressure of your own foot on the pedal?

I presume you mean the cruise... but you never know. The cruise will always try to hold the set speed. It will also try to do so without lugging the engine. Your tire size is part of the problem. Many people re-gear when they increase tire size, however your increase is minimal and would not be worth the money for the gain you will get.