I have a 2005 Dodge diesel 2500, I am pulling a 6500# bumper hitch trailer.we are going to the mountains (NC)this next week, driving from west KY>I like my dodge diesel and it pulls my trailer great.but, I am very concerned about the down hill (mountain) pulls that I am going to have to make.my truck does not have an exhaust brake,a 2005 dodge diesel transmission only has 1,2,D and you have tow haul on the end of the shifter.QUESTION:when I start down a long mountain, what gear selection do I make, what is going to help me hold that load back???????????I have heard that the diesel engine has little to no braking ability, so do I just ride the brakes until I go over the mountain side when the brakes get hot and go,as you can read into my posting, I am somewhat concern about this.I just bought new tires and shocks for the truck, I may have been better served to have purchased an exhaust brake.but, have heard the 2005 dodge diesel transmission does not like exhaust brakes so well.can any of you, that has pulled with a 2005 dodge diesel give me some pointers on how to handle the load.seems like trading the tuck for one with an exhaust brake or not going are not options at this time. My friend will also be traveling with us, he has a 2010 gmc 2500 diesel and he is pulling a heavy, hitchhiker 5th wheel, but I do not think he has an exhaust brake either. however, he has the Allison transmission that may give him better downhill control.Thanks for any and all responses, as you can tell I am a bit worried.

Run it in D and tow haul. Down shift to 2 or 1 as needed. The mountains in NC are not that bad. Your friend will only need to tap his brake petal a time or two to downshift. He will love his transmission.

You seem to be overly concerned about something that should not be an issue with a trailer that size providing that the trailer and truck brakes are in good shape. Think before you start down large hills. The lower the speed and gear that you start in, the better control you will have throughout. Personally if I had that much concern about the capability of my truck with a load that is way below its designed capability, I would probably upgrade the truck.

Your truck will have no problem holding back a 6500 lb trailer without an exhaust brake on highway grades. If you ever get on a very steep grade that requires more wheel braking than you are comfortable with you can downshift manually, then slow with the brakes until the transmission makes the shift or start in low gear from the top.

My current TV (Tundra) isn't directly comparable, but I had similar concerns on a recent trip to NC pulling a similarly sized TT. For me, my anxiety was indeed (very) overblown. I manually downshifted a few times and rarely had to tapped the brakes on descents ... it was no big deal.

Couple of things about mountain grades.1. Never drive down faster than you drove up the grade. Up or down grades, if other vehicles are flying around at higher speeds you may want to run your flashers to warn the fast drivers. Depending on state laws. i.e. do as the truckers do. Just because the speed limit says 65 down the grade doesn't mean you have to drive that fast. 2. Let your engine hold you back going down the grade.3. If you need to apply your brakes, apply them fairly heavy to bring your speed down lower than your safe down hill speed. Then release the brakes. Do not ride your brakes down a grade.You will do fine. Better to be a concerned driver than someone flying down a grade that doesn't have any worries or concerns and probably was just lucky to qualify for a drivers license. Not sure about temps back there in NC this time of year. In mountain passes sometimes you have black ice in the shaded areas of the road that can catch you by surprise. Just be aware of it.

Down hill pull question | Good Sam Community

23 Replies

pronstar
Explorer
Oct 16, 2013
Compression braking on a gas engine is a misnomer...it's really vacuum braking.

All 2nd-gen (and newer) D-Maxes have exhaust brakes, via the variable-vane turbo.
Newer Fords and Dodges also do this with their turbos.
wnjj
Explorer II
Oct 16, 2013
Turtle n Peeps wrote:
Me Again wrote:
Turtle n Peeps wrote:

To make a long story short; compression. It takes a lot of energy to compress a 16 to 22 to 1 piston. And if your foot is off of the go pedal there is no bang in the cylinder so your trying to compress a lot of air and the down hill grade energy is doing that.

When my dad bought his 93 diesel he was going to take a trip to Alaska and was freaked about doing it because of the same old tired stories he heard about diesels. When he got back he said that those people don't know what they are talking about. He said it held back better than my old truck. (Which was a gas small block with 3 speed auto). Remember, this is with an old 4 speed diesel with no TH or anything like that.

In short, you have nothing to worry about. Stick it in TH and drive it how fast or slow you want to go.

And that energy to compress the cylinder is almost all returned when it un-compresses on the down stroke. Until you have owned a Dodge/Cummins people do not seem to get it. The V8's seem to hold back better.

Chris

Sorry, but nothing un-compresses on the down stroke. The valves are closed on the power stroke.

Take a syringe and draw in a bunch of air and then put your finger over the hole and compress the air and then leave go of the plunger. It will spring back about 50% and then it will take a lot of energy to draw it out to the original position.

So you tell me; why does the V8's seem to hold back better? Why is the Cummins special, or not so special in this case? I have owned over a half a dozen diesels V8's and in lines and all have held back just fine.

Like I said, my 6.5 with 4L80E holds back better than my gas SBC with T400. My Dmax with VV turbo and TH is no contest in hold back power. It will kill any gas engine I have ever owned on hold back power.

Yes, the valves are closed which is why the pressurized air now pushes back down on the piston. Compression brakes work by exhausting that pressure before the piston travels down. Without one the only thing compressing that air does is make a marginal amount of heat on any engine but mostly returns the energy right back to the piston.

The reason a gas engine has more engine braking is because it is throttled (also one of the reasons it is less efficient at other than full throttle).

Maybe the turbo on a diesel creates enough exhaust restriction to help?

EDIT: I mean even on a non-EB older diesel. I know they intentionally use them for braking on newer ones.
45Ricochet
Explorer
Oct 15, 2013
Well I can't explain it other than my Cummins is faster downhill than my boat anchor .
I'm sure the software/ tranny has something to do with it.

LOL "MY 6.5 holding back better" ain't that the truth. She reminded me of ..... ah forget it.
Turtle_n_Peeps
Explorer
Oct 15, 2013
Me Again wrote:
Turtle n Peeps wrote:

To make a long story short; compression. It takes a lot of energy to compress a 16 to 22 to 1 piston. And if your foot is off of the go pedal there is no bang in the cylinder so your trying to compress a lot of air and the down hill grade energy is doing that.

When my dad bought his 93 diesel he was going to take a trip to Alaska and was freaked about doing it because of the same old tired stories he heard about diesels. When he got back he said that those people don't know what they are talking about. He said it held back better than my old truck. (Which was a gas small block with 3 speed auto). Remember, this is with an old 4 speed diesel with no TH or anything like that.

In short, you have nothing to worry about. Stick it in TH and drive it how fast or slow you want to go.

And that energy to compress the cylinder is almost all returned when it un-compresses on the down stroke. Until you have owned a Dodge/Cummins people do not seem to get it. The V8's seem to hold back better.

Chris

Sorry, but nothing un-compresses on the down stroke. The valves are closed on the power stroke.

Take a syringe and draw in a bunch of air and then put your finger over the hole and compress the air and then leave go of the plunger. It will spring back about 50% and then it will take a lot of energy to draw it out to the original position.

So you tell me; why does the V8's seem to hold back better? Why is the Cummins special, or not so special in this case? I have owned over a half a dozen diesels V8's and in lines and all have held back just fine.

Like I said, my 6.5 with 4L80E holds back better than my gas SBC with T400. My Dmax with VV turbo and TH is no contest in hold back power. It will kill any gas engine I have ever owned on hold back power.
Me_Again
Explorer III
Oct 15, 2013
Turtle n Peeps wrote:

To make a long story short; compression. It takes a lot of energy to compress a 16 to 22 to 1 piston. And if your foot is off of the go pedal there is no bang in the cylinder so your trying to compress a lot of air and the down hill grade energy is doing that.

When my dad bought his 93 diesel he was going to take a trip to Alaska and was freaked about doing it because of the same old tired stories he heard about diesels. When he got back he said that those people don't know what they are talking about. He said it held back better than my old truck. (Which was a gas small block with 3 speed auto). Remember, this is with an old 4 speed diesel with no TH or anything like that.

In short, you have nothing to worry about. Stick it in TH and drive it how fast or slow you want to go.

And that energy to compress the cylinder is almost all returned when it un-compresses on the down stroke. Until you have owned a Dodge/Cummins people do not seem to get it. The V8's seem to hold back better.

Chris
Terryallan
Explorer II
Oct 15, 2013
davisenvy wrote:
I am so tired of hearing "diesels have little to no engine breaking". I'm a native of NC mountains and diesels have plenty of engine breaking.
The rule of thumb is go down the mountain a gear lower than the gear you came up it in. So if you had to use 3rd to climb it, use 2nd to go down it.
Stab the breaks instead of riding them to slow down.
Pick a speed (let's say 35mph). Stab the brakes until you hit 30mph then let your speed gradually climb to 35mph then stab the brakes again back down to 30mph. If you have to do this more than once every 7 sec or so, gear down again.
IGNORE THE PEOPLE BEHIND YOU! Truth be known, half of them are probably glad you are going that slow so they can hang their cameras out the window.
Hurry the leaves are already changing at higher elevations!

Just because you don't like it. Does not mean it is not true.

I have brought diesels down Black Mountain. Left the brake check area in 3RD gear (had 13). It nearly blew up before I could hit the brake. It's like coming down in netural. Diesels only have braking if they have a exhaust brake, or trany brake, or other outside braking. No natural braking like a gas engine.
maxwell11
Explorer
Oct 14, 2013
Thanks for your replys,

we pull out today and when home, I hope to report no problems
and with all my bells.

as old teamster freight haulers would say,

The teamsters took great pride in their teams and the music produced by the bells. If a wagon got stuck in the muddy roadway, broke down, or required help, he was expected to give up his bells to the man providing aid. Thus the teamster would be disgraced if he arrived without his bells.

old saying "I will be there with bells on"
davisenvy
Explorer
Oct 14, 2013
I am so tired of hearing "diesels have little to no engine breaking". I'm a native of NC mountains and diesels have plenty of engine breaking.
The rule of thumb is go down the mountain a gear lower than the gear you came up it in. So if you had to use 3rd to climb it, use 2nd to go down it.
Stab the breaks instead of riding them to slow down.
Pick a speed (let's say 35mph). Stab the brakes until you hit 30mph then let your speed gradually climb to 35mph then stab the brakes again back down to 30mph. If you have to do this more than once every 7 sec or so, gear down again.
IGNORE THE PEOPLE BEHIND YOU! Truth be known, half of them are probably glad you are going that slow so they can hang their cameras out the window.
Hurry the leaves are already changing at higher elevations!
time2roll
Nomad
Oct 14, 2013
If I had a dime for every post that said something to the effect of "how will you stop it with your half ton" I would buy you an exhaust brake.
alboy
Explorer
Oct 14, 2013
I pulled a similar sized TT (6800 lbs) with my 06 3500 all thru the mountains of BC. and the USA, the TT almost acts like a parachute and will not even push the truck on a 6 % grade.In reality the truck handles a TT that size like its not even an issue.

Forum Discussion

Down hill pull question

23 Replies

About Travel Trailer Group

Related Content

Payload changes on Hills

Texas Hill Country

Newbie power question

parking on hill

Another solar question.