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Discussion Starter #1
Has anyone figured out how to stop the transmission from shifting down several times going down a hill?? I have the 3.6 gas engine in a 2014 3500. I've tried everything! Cruise, no cruise, tapping the gas pedal, throwing it in N and coasting. I hate it! I don't want my engine reving that high. It's ridiculous. So now when I start going down a hill, I have to slow way down while everyone else is blowing by me. Is it in the transmission, ECM, or the TCM? Someone out surely has figured it out by now.
 

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It is programed into the ECM and you are not going to stop it. I hate it too. My diesel will do it if I have it in D but I can shift it into manual and then up to 6th and avoid the issue. Most new cars seem to do this and it would be great to have an aption to avoid it. Brakes are cheaper to replace than engines! Sorry.
 

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In short, they all do it, it wont hurt anything, there is no way to stop it. Tow/haul and cruise seem to make it worse. Neutral is an option.
 

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To each his own, but growing up in the Rockies, I've always downshifted on hills to save brakes. Flat-landers ride their brakes down the long grades off mountain passes, while they're wondering what all the run-away ramps are for. I actually like that the PM downshifts itself. Sometimes I even pull it over into manual-select to downshift even further. Sure, engine revs get noticeably louder, but that's not hurting anything. I've never seen it even get close to red-lining (6400rpm).
 

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Discussion Starter #6
Y'all don't think it's hurting anything? I don't want my engine reving that high. These engines are known for top end problems. Now I know why. Over reving. There has to be a way to turn it off somehow. Say what you want, but that engine should not be reving that high. I've been driving over 40 years and have never needed any help going down a hill.
 

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I agree completely but as Mr. Dylan says “The times they are a changing.” Nearly all cars do this now. I have the diesel and shifting to manual is so easy I do it. I just bought a 2008 low mileage AZ Rav4 for NH partly so I can avoid it. I hate it and believe we should have an option out of the downshift. Its just some lines in a program. I began legally driving at 14 in Vermont so I have 56 years behind the wheel and I don’t plan to rev the pi$$ out ot my engine either.
 

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Its normal, and these engines can rev high.
How high do you think is safe over the long term? Is revving up the engine worse when using it to slow down vs. speeding up?

When I have cruise control engaged on my 2014 gasser and I start going up a hill, the transmission will drop as low as 3rd gear and the engine will rev up to 6500 RPM if I don't catch it in time and turn cruise off.

Going downhill I don't think I've seen it go over about 5500 RPM but for longer periods of time.

I would hope that, since they're willing to idiot-proof the downshifting mechanism to protect the brakes, they would idiot-proof it to protect the engine as well. For example, I don't think I can downshift into 2nd gear when going 60mph.

The more annoying aspect is just the inefficiency. When I'm in hilly areas, I want to pick up speed going downhill to carry my through the uphills. Instead, I lose all that momentum and use a lot more fuel getting up the hills
 

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Discussion Starter #10
I have to actually ride my brakes all the way down the hill so I can keep the RPMs from going over 3,500 RPMs. I don't even like that many RPMs. So I'm actually using my brakes more! But I'm not going to rev my van that high. It's ridiculous.
 

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I have had some success accelerating briefly after the downshift to 5th enough so that transmission upshifts back to 6th when going down a big hill. Often it stays in 6th the rest of the way down....
 

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Over 60 mph I totally understand the downshift to 5th. That is mechanically reasonable.

It is that second downshift to 4th that sends the rpms past 4000 rpm that realllllyyyyyy bothers me.

And then the Brake warning light comes on for the steeper grades.

I'm convinced they did zero mountain testing of this van.
 

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I agree completely but as Mr. Dylan says “The times they are a changing.” Nearly all cars do this now. I have the diesel and shifting to manual is so easy I do it. I just bought a 2008 low mileage AZ Rav4 for NH partly so I can avoid it. I hate it and believe we should have an option out of the downshift. Its just some lines in a program. I began legally driving at 14 in Vermont so I have 56 years behind the wheel and I don’t plan to rev the pi$$ out ot my engine either.
Interesting. having test driven many new vehicles the last 2 years, none if them did this. And I live in a valley.
 

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I have had some success accelerating briefly after the downshift to 5th enough so that transmission upshifts back to 6th when going down a big hill. Often it stays in 6th the rest of the way down....
When I tried this the RPM's just went up and stayed in 4th?
 

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For a point of reference I'm talking about the mountains out west. I should keep a list of what roads have set off the brake warning. The two I remember is in CO...heading west after the Eisenhower Tunnel on 70. And then heading east coming down Independence Pass.
 

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For a point of reference I'm talking about the mountains out west. I should keep a list of what roads have set off the brake warning. The two I remember is in CO...heading west after the Eisenhower Tunnel on 70. And then heading east coming down Independence Pass.
He have some pretty steep hills here too lol
 

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I agree completely but as Mr. Dylan says “The times they are a changing.” Nearly all cars do this now. ......cut.....
Agree, and much of it is simple math that is unavoidable with standard drivetrains. It’s mostly driven by fuel economy requirements.

Engines are now smaller in displacement, so can provide less engine braking at same RPM. Additionally, top gear is taller than they use to be, so engine starts out at lower RPMs with less “leverage” to help slow the van on downhills.

And let’s not forget these vans are more aerodynamic (granted with larger front area) and roll easier too due to lower rolling resistance tires, etc. It all adds up when gravity takes over. The rest of the time we love it when MPGs are much higher than 40+ years ago when large V8s didn’t even have an overdrive.

The best fix I’ve used on large and heavy motorhomes in the Rockies is to go slower so the transmission can be in a lower gear, and thus provide more engine braking force at same RPM. That works every time but requires slowing down.

Even on my fairly light van with large 6.8L V10 I had to use 2nd gear to avoid riding brakes on part on Teton Pass. That was worse than I-70 Ike tunnel descend because of tight curves requiring much lower speeds.
 

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I hate this too. If it only downshifted into 5th gear it wouldn't be so bad, but it will go into 4th with very high rpm and who knows maybe 3rd gear too if I let it go that far. Once it downshifts it is difficult to get it to upshift back into 6th. It requires applying throttle for about 10 seconds, gaining a lot of speed in the process. I ride the brakes going down mountains to try to keep it from downshifting, but would rather be coasting and saving my engine, transmission and brakes from unnecessary wear and tear like I have for the past 53 years of driving. There is no way this intended design is a good idea. What is wrong with our engineers these days?
 

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Surely there is a way to modify the programming on these vans to change this undesirable trait. I will not be buying Promasters in the future if this can not be fixed. It is a poor design that causes undue wear on the engine and transmission, poor fuel economy and excessive brake wear. It is dangerous when going down a mountain and you have to slow down to keep it from over revving the engine if you have heavy traffic behind you.
 

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