using lower gear on a long downhill

[pduutkedu]

Hi, guys

Is there any side effect if I use lower gear on a long downhill as an alternative to brake? This way it could save some brake, so what am I paying for?

Also, I usually gear up to N at a long red light, and every time when I switch it back to D, there is a little shake with the car...I am sure there is nothing wrong with the transmission, so is that shake normal or harmful to transmission?

Thanks!

 

[ObeseFieldMouse]

on long downhills, gearing down is a good idea, just in moderation...definatly drop it out of overdrive (5th) but i personally wouldnt let it rev over 3000rpm.

about that jerk...thats normal, but completely unnessicary. leave it in drive. that bump is the tranny clutches locking up really quickly...that will eventually cause the low/reverse clutch pack to wear out prematurely.

 

[pduutkedu]

Thanks for the quick reply. How do you know whether you are in the 5th gear or not? And, about changing gear while running, all I know is leave the foot away from the gas pedal, and my foot is usually on brake while doing this...is this the right way?

 

[spyne]

Downside is a bit more gas used, since the engine is turning more RPMs. Plus side is that on long, steep downhill runs, you'll still have brakes when you need them.

 

[pduutkedu]

Can someone move this post thread to the 'General' forum? My bad. Thanks a lot.

 

[jeober]

Downside is a bit more gas used, since the engine is turning more RPMs

With some vehicles injectors are turned off on long coasts - don't know about 4runner. I wouldn't worry about the gas usage; better to keep the brakes cooler. You can shift the transmission whether braking or not. Today's electronically controlled transmissions and electronic throttle control prevent harmful shifting.

Also, I usually gear up to N at a long red light, and every time when I switch it back to D

Seems like wasted motion to me - don't understand your reason for it.

 

[pduutkedu]

Well, the only reason I switch to N at long temporary stop is to save some engine wear out, but maybe that doesn't make sense. So, what's the occasion to use N?

 

[Uneek]

With some vehicles injectors are turned off on long coasts - don't know about 4runner.

The V8 or V6 for that matter aren't one of them. As far as I know, I don't think Toyota has any variable displacement or displacement on demand engines. Mercedes Benz, GM and Honda does.

 

[Uneek]

Well, the only reason I switch to N at long temporary stop is to save some engine wear out, but maybe that doesn't make sense. So, what's the occasion to use N?

IMO, I think engine wear would be lower in gear because the engine idles lower in drive or reverse than neutral.

You want to use neutral when you need the 4R pulled or pushed for a short distance, i.e. if you're parked on a slope and you want to move the truck down a bit without starting the engine again. I don't Toyota recommends the 4R being towed on its wheels, either on a flatbed or dollies. Also, if you have a V6 4WD, you need to be in neutral to shift from 4H to 4L.

 

[jeober]

To help clarify previous info:

1) Variable displacement engines selectively deactivate cylinders by disabling valves.

2) Injectors turning off during coast is a fuel economy provision. You would not be aware when this happens or if your engine calibration provides for this. Your engine only pumps air when this happens.

Also, engine load is higher in drive but any wear difference is immeasurable and therefore inconsequential.

 

[spud72]

To help clarify previous info:

1) Variable displacement engines selectively deactivate cylinders by disabling valves.

How can it disable valves? Isn't it direct mechanical linkage on every engine from cam lobe to lifter?

 

[jeober]

The information is at your fingertips. Good thing Al Gore invented the internet!

 

[ObeseFieldMouse]

"variable displacement" is rather vague because every auto maker that had or has one, did it a different way.

turning off injectors is a "variable displacement". the varying displacement is viewed in terms of the displacement being utilized, not the physical displacement available.

 

[pduutkedu]

Tried this method several times these days and it works well....Sometime while leaving highway, the rpm jumped over to 4000 before the car slowed down.

Here just wanna give a safety comment about this topic. Better be careful when using this with some other vehicle close behind. It might not be safe for them because they don't see your brake light on for speed reducing like using brake.