Downshifting on long grades

[BuckeyeChuck]

A few days ago I encountered a 4.5 miles long 6% downhill grade. I down shifted to 2nd gear to slow my speed. I was able to stay at 55mph but the engine was raving at 5000 RPM. The red line MY 6.2L Ford gasser is 6000RPM. Does anyone see a problem doing this?

[jgourlie]

I once posed the same question and the response I got was this. Would you rather pay for a new transmission or a new set of brakes.

I decided it was better to wear out my brakes on my truck than potentially damage the transmission or engine.

hope that helps,

[325BH]

Originally Posted by BuckeyeChuck

A few days ago I encountered a 4.5 miles long 6% downhill grade. I down shifted to 2nd gear to slow my speed. I was able to stay at 55mph but the engine was raving at 5000 RPM. The red line MY 6.2L Ford gasser is 6000RPM. Does anyone see a problem doing this?

You are starting to see where a gasser has its limitations on engine braking with heavy loads. I leverage engine braking when I can, but 5k rpm is starting to get up there. I would probably use both, engine and brakes, so neither is being overtaxed.

When braking on long steep grades I employ the brake-and-release-brake-and-release tactic... rather than applying brakes constantly to keep a constant speed. The brake-and-release means you will slow-then-speed-up, but is is easier on your brakes.

For brake jobs, I replace rotors along with pads. It is a little more expensive, but keeps the brakes in better shape. This is especially true for our tow vehicles that get worked. On those steep grades, nobody is telling me I wasted money on fresh rotors.

I also replace my transmission fluid every year. It doesn't cost much but pays dividends. Since I am constantly replenishing the fluid, I never worry about a full flush.

[Jim34RL]

Truckers have always stated that what ever gear you ascend the grade with is the same gear you use to descend that grade. One thing about the new generation of diesel trucks offers a exhaust brake as standard now. This is a great asset when descending a grade.

The new Ram trucks with the Cummins Diesel engine has a nice feature. When the exhaust brake is activated and the cruise control is activated this will hold the truck at the set speed with load as you descend a grade.

[crookedread]

The braking supplied by the engine is supposed to work in conjunction with the tv and trailer brakes. Trying to let any one of the tools do all of the work will just over stress and damage that tool. There's really no reason to damage anything. When going into a steep descent, lower your speed before cresting the hill. Then use all of yours tools so none are damaged.


Crookedread
2016 2500 Duramax
2011 Stealth 2312

[Ford Idaho]

Living in the NW has it's ups and down's, depending on the grade I would have done one gear higher and a little more brake.

If you have the brake controller set right the trailer should help hold its own weight with a little assist from the truck.

[chuckw5kav]

I see nothing wrong with going down a hill a 1000 rpm's
below what your truck is rated at, mine and allot of
pickup's now have engine brakes for such a thing.

As far as the OP wearing out his brakes on a 6 percent
grade don't believe it. Brakes will get hot if you stay on
them or keep hitting them after a mile or so going
down a 6 percent grade with your trailer pushing you
and then you have no brakes.

If you are going to use you brakes I recommend you
come off a hill with a 6 percent grade very slow and
only use your brakes every so often to keep you
slowed down, do not, I'll say it again do not stay on
your brakes, you will heat them up to the point that
you will not have any brakes at all. This not because
you wore them out, it's because they got so hot
they will not work.

It's best to let your truck engine do the work and
save your brakes, trust me I have taken big rigs
off of 12 to 14 or more mile downhill grades
without jake brakes (engine brakes) just using
my truck bakes and made it without any
problems. But you have to use you head and take
it slow, if people want to pass you so what, when
you get to the bottom you and your family will
be safe and the wife and kids will not have that
look of horror in their eyes if you loos your bakes
half way down that hill

[tkarper14]

Well said chuckw5kav

[crookedread]

Obviously this is a gasser so comments from diesel drivers really have no bearing. I crossed a 6200 foot pass with my tundra towing a 7800 pound toy hauler. I knew before I crested the hill that I didn't have any trailer brakes. Slowed down, geared down and never saw anywhere near 5000 rpms. Sustained, that's too high for me! Used the brakes intermittently without worry about over heating! I had plenty of reserve to come to a complete stop if necessary.

Just came over same hill with diesel on tow haul and exhaust break on. Never touched the brakes.


Crookedread
2016 2500 Duramax
2011 Stealth 2312

[lbrjet]

Your truck can do 5K RPM all day long with no ill effects on your engine or transmission. You are using it exactly as it was designed to be used. You could do 50 mph with minimal braking next time if you are concerned.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[waiter21]

Ford does some weird things with their newer transmissions regarding downshifting and braking.. 5000 rpm bothers me more than it does the engine or tranny. :-)

I have a rule thats served me well driving through the Rockies. I never go down a hill any faster than I could go up the hill.

On my 2001, yes, I manually downshift and slow down to find a speed where I'm not building up speed, and the engine is turning around 4500 rpm and doing the majority of the braking. This means slowing down, manually selecting a lower gear, turning on the four way flashers, and enjoying the ride.

There's no sense in smoking the brakes where they get so hot that I find myself using one of those "Runaway truck ramps"

[NoviBill]

#1 reason not to use just your brakes - they overheat and fail
If you have been using your brakes on a long steep downhill stop every 2-3 miles and check your brakes. First use the back of your hand near the lugs without touching. If you feel the heat the brakes need a rest.

Running the engine for short periods 1000 RPM below it's red-line is not an issue.

Waiter21 has it right, go down no faster than you went up.

Many vehicle have a downhill braking mode when in cruise control (my 2006 E450 does). If cruise is on and set to 50mph it will shift and adjust the engine to do it's best to achieve 50mph on a downhill grade.

[Ford Idaho]

Originally Posted by crookedread

Obviously this is a gasser so comments from diesel drivers really have no bearing. I crossed a 6200 foot pass with my tundra towing a 7800 pound toy hauler. I knew before I crested the hill that I didn't have any trailer brakes. Slowed down, geared down and never saw anywhere near 5000 rpms. Sustained, that's too high for me! Used the brakes intermittently without worry about over heating! I had plenty of reserve to come to a complete stop if necessary.

Just came over same hill with diesel on tow haul and exhaust break on. Never touched the brakes.


Crookedread
2016 2500 Duramax
2011 Stealth 2312

Right, none of us "diesel drivers" have ever towed with a gas engine....

Sigh!

[crunchman12001]

Originally Posted by Jim34RL

Truckers have always stated that what ever gear you ascend the grade with is the same gear you use to descend that grade. One thing about the new generation of diesel trucks offers a exhaust brake as standard now. This is a great asset when descending a grade.

The new Ram trucks with the Cummins Diesel engine has a nice feature. When the exhaust brake is activated and the cruise control is activated this will hold the truck at the set speed with load as you descend a grade.

X2 to a point.
As a CLASS A CDL license holder, you will want to be in a lower gear going down hill then you would up the hill.
Use stab braking techniques "apply your brakes to 5 mph below your safe speed, release brakes , coast to "accelerate" to safe speed and repeat"
In newer trucks, the tow/haul will allow the engine brake to work when applying the brakes in combination with a lower gear, even with gassers. Never downshift on a manual tranny going down hill, you could get stuck in neutral.
The last thing you want is the brakes to get hot enough to get brake fade. (They stop working).
Always keep an eye out for escape ramps.
Be safe out there.

[bob caldwell]

There is a brake pad available that is semi-metallic and ceramic....more heat, the better they work

[crunchman12001]

Originally Posted by bob caldwell

There is a brake pad available that is semi-metallic and ceramic....more heat, the better they work

Not being argumentative, but wouldn't the increased heat caused from the friction on the ceramic pads be detramental to the rotors, causing warpage and decreased braking capacity? We are all learning here.

[john5646]

Just throwing this out there.. drilled and slotted rotors with pads all four corners. Under 300.00 way under.
I run them on all my stuff and started using on our work trucks I confirm improved millage.
Just felt that all the talk of brakes here this may be of interest to some.
Happy braking.

[NoviBill]

Originally Posted by bob caldwell

There is a brake pad available that is semi-metallic and ceramic....more heat, the better they work

Working better "hot" is only true to a point, brake fade (actually catastrophic failure) occurs when the brake fluid heats to boiling. At that point you cannot apply enough pressure to stop the vehicle.

[bob caldwell]

True...and if one wanted the best...carbon fiber

[bob caldwell]

Two trip across the Rockies at 17,500, haven't had rotor or drums going out of round....and, was on state and county roads with a lot of switch backs