[densell]

During my commute to work there are several hills with traffic lights at the bottom of them, some have stop signs. When I'm at the crest of the hill, I use the manual downshift button to drop into 5th, then as I come down the hill I generally use it to run down into 4th, 3rd, and 2nd. I find this adds some good engine braking, so that my use of the truck breaks are limited. As I run this route daily, I'm sure over time it will increase the life of my breaks.

I have 2 questions (perhaps some of you guys with good mechanical knowledge can answer). First, by doing this, am I putting undo wear and tear on the transmission and engine - thus, negating the gains I'm getting from not using the brakes ?

Second, would just hitting the tow/haul button at the creast of the hill be better. That would allow the transmission to decide how to apply the engine brake.

Any feedback or comments are welcome.

Thanks in adavance.

 

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During my commute to work there are several hills with traffic lights at the bottom of them, some have stop signs. When I'm at the crest of the hill, I use the manual downshift button to drop into 5th, then as I come down the hill I generally use it to run down into 4th, 3rd, and 2nd. I find this adds some good engine braking, so that my use of the truck breaks are limited. As I run this route daily, I'm sure over time it will increase the life of my breaks.

I have 2 questions (perhaps some of you guys with good mechanical knowledge can answer). First, by doing this, am I putting undo wear and tear on the transmission and engine - thus, negating the gains I'm getting from not using the brakes ?

Second, would just hitting the tow/haul button at the creast of the hill be better. That would allow the transmission to decide how to apply the engine brake.

Any feedback or comments are welcome.

Thanks in adavance.

I do similar things when driving with mine, when I am driving through the mountains I just leave it in Tow/Haul. Touching and releasing the brake pedal going downhill will cause a downshift, do it again and it will downshift again. To me this is easier than constantly hitting the paddle.

 

[navistar45]

My thought on this, as mentioned use tow haul. In the end, i would prefer to replace a set of pads, then i would a tranny.

 

[snakyjake]

I'm still waiting for a mechanical expert to respond, but in the meantime here's my logic:

I don't think there's any added mechanical stress the drive train is not designed to handle.

Most of the engine wear and tear is caused by friction. So I presume higher RPM's equals more friction on anything that rubs (valves, rings, pistons, etc).

However, engine braking super cools the engine and pumps a lot of lubricating oil through the system, which may reduce the friction and wear effect.

Brake pads might not be the only thing need replacing, but could be warped rotors and calibers too.

I think the key to engine mechanical longevity is to keep those RPM's low (assuming you're doing everything else the manufacturer recommends).

But in the end, not too many people keep their vehicle until its dead. Better to trade it or sell it before it is too old to get rid of.

Jake

 

[navistar45]

I cant see engine wear being an issue, unless the shift is at high rpms. The wear will be in the shifter, and the tranny itself.. More shifting, equates to more wear.. Likewise, more brake use equals more friction, meaning more wear.. There is no way around the wear factor, it's just the cheapest and easiest to repair, is the brakes..

 

[06kma]

The autosequential shift mechanism doesn't allow you to down shift to early and damage anything so I would think the engineers designed that specifically to prevent premature wear or failure.

I use the column shifter to downshift over the tow haul when empty becuase I don't like the pattern of shifting when I'm not towing. It is a little jerky and on gravel/snow it will cause the tires to break free sometimes.

No true mechanical knowledge for you and I will trade out the truck in two years so I'm not looking at long term effects. Mine will go down the road with 60,000 miles or so then I don't worry about brake pads, front end work etc.

 

[snakyjake]

I cant see engine wear being an issue...

You don't think running the engine at higher RPM's creates more engine wear?
More RPM's equals more piston shear against a cylinder. More camshaft revolutions, more valve seats, more bearing movments. It's more of everything.

Typically the engine creates compression to power the vehicle weight. This is the reverse case; decompression is created to decelerate the vehicle weight.

Anytime a mechanical device is doing work, it's wearing...otherwise it wouldn't be work.

 

[densell]

Thanks for all of the replies. Seems using the the manual downshift and/or the tow haul might not be the way to go. I get the impression that the wear and tear on the engine out weighs the benefit of the savings on the brakes.
Seems Ford need to develop a system like they have in Hybird vehicles whereby engine braking recharges the batteries. It just is such a waste of energy when you consider the mass of the truck and the force required to bring it to a stop everytime we brake.

 

[navistar45]

You don't think running the engine at higher RPM's creates more engine wear?
More RPM's equals more piston shear against a cylinder. More camshaft revolutions, more valve seats, more bearing movments. It's more of everything.

Typically the engine creates compression to power the vehicle weight. This is the reverse case; decompression is created to decelerate the vehicle weight.

Anytime a mechanical device is doing work, it's wearing...otherwise it wouldn't be work.

Sure it will, thats logic. But look at it like this when it comes to the tranny.. Which do you think will last longer, the tranny in a bus going up and down the highway, or that same bus doing street corner to corner stop and starts? When i do a manual down shift in my 11', my switch to do the down shift gets wear, the tranny gets to often make a rougher downshift how ever many time i decide to press the button, the driveline gets a bit of shock from the down shifting, the engine rpms climb higher,and then the brakes get used as well.. If you let tow mode do some of this work, the so called engine brake will aid and everything becomes a bit less worked/used, depending on speed and load.. I'am not saying a manual down shift isnt ever called for, but as the orig poster decribed, i cant see any need in it ..

 

[mudguppy]

... Seems Ford need to develop a system like they have in Hybird vehicles whereby engine braking recharges the batteries. It just is such a waste of energy when you consider the mass of the truck and the force required to bring it to a stop everytime we brake.

they did in '02, although it was a system that accumulated, stored, and released mechanical energy to assist with braking/starting to improve fuel economy. it was a high-pressure gas accumulator tied into the rear driveline; it would use the truck's driveline energy during braking to compress gas in one tank and release it back through the driveline into another tank for take-off.

not sure why they didn't go forward with it.