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Discussion Starter #1
I drive in the mountains a lot. Im used to putting it in tow/haul or manually downshifting. This thing downshifts on its own and wont upshift unless i accelerate. Really sketchy when it grabs a random downshift in snow conditions on a steep descent. Is there anyway to make that stop? What’s the point of tow/haul or manual mode then? My van is brand new...
 

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MMXVI - L2H2 in IN
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It's normal, it's designed around it's maximum payload.
Downshifting is for engine braking going down and protects the transmission from overheating when going up.
Tow/haul mode delays shifting.
In time you will learn how to feather the gas pedal just so.

Not to sound like an a$$ but it's in the owners manual.
 

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From the manual: When operating in TOW/HAUL mode, transmission upshifts are delayed, and the transmission will automatically downshift (for engine braking) during steady braking maneuvers.

So maybe tow/haul isn't the best for slippery conditions if steady (prolonged?) braking triggers a downshift.
 

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Discussion Starter #4 (Edited)
From the manual: When operating in TOW/HAUL mode, transmission upshifts are delayed, and the transmission will automatically downshift (for engine braking) during steady braking maneuvers.

So maybe tow/haul isn't the best for slippery conditions if steady (prolonged?) braking triggers a downshift.
Correct. This occurs NOT in T/H. The service tech said to drive it hard. It takes 3-5k miles to learn driving habits and set shift points.

I’m very familiar with mountain driving and large trucks. The promaster does not drive like most trucks. Sorry if I wasnt clear orginally. It felt like I’m going to blow the motor up at 4k rpm constantly in a new van!
 

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This thing downshifts on its own and wont upshift unless i accelerate.
When going downhill, think of your accelerator as a messenger to the computer (not the fuel injectors).

Foot ON accelerator (even very lightly) = "I want to maintain my speed, or go faster."

Foot OFF accelerator = "I don't want to go faster than my CURRENT speed."

If the computer knows that you don't want to go faster than the speed you were going when you removed your foot from the accelerator, and you are gaining speed, it will downshift to initiate engine braking.

On steep declines, enjoy the engine braking and be happy that you are not overheating your brakes.
 

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MMXVI - L2H2 in IN
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That's about the best explanation I've read so far.
 

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Promaster 3500 Gear hunting at highway speeds

All- I have a slightly different issue w/ my new 3500 chassis. I have a new Winnebago Trend motorhome on this chassis. At hwy speeds say 65-70 it will not hold 6th gear, overdrive for long. In the slightest headwind- it downshifts, regains speed and then upshifts back into 6th. Tow haul mode does not help much. So far all my driving is in flat Florida. Owners manual say if you experience frequent gear shifting, pick a lower gear. Think its ok to run this in 5th at say 2800 -3000 rpm for long periods?? Owners manual say that is preferable to the gear hunting. Anyone else experience this issue?? Thanks all. Do appreciate the info posted here.
 

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I will bet the Trend is overweight for the tranny shifting points. It may learn them on its own one never knows.
 

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I'm in Florida also and have a lightly loaded high roof 159. In my travels if I'm in strong head wind or hillier conditions I will drive a little under 70 in 5th. At around 3,000 rpm it is more in it's powerband and will do much better.
 

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On flat roads, at highway speeds, extra vehicle weight doesn’t really add much to load on engine, so it wouldn’t explain all the shifting/hunting.

On the other hand, the Trend is listed at 90” wide and 10-ft tall, which makes it a lot larger in cross section than a standard ProMaster; even compared to a high roof. Because the Trend uses the same final gearing, as highway speeds climb, there isn’t enough reserve power to stay in 6th.

Unfortunately, ProMaster transmission gear-ratio jump between 5th and 6th is fairly wide, so when it drops into 5th, the engine is too lightly loaded for optimum fuel economy. I’m fairly certain that’s what leads to hunting.

I looked at Trend, REV, and similar motorhome designs, and based on reports of 12~13 MPG fuel economy, what you report is not surprising.
 

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That is about what I have to do, but going steep or long downhill, I have to apply brake whith my left leg to keep a comfortable speed to that 8000 pounds, I was not use to do that, but it is the only manner I found since now to manage whith this vehicule, I asked for a new programmation whitout success...
 

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I would greatly prefer using the manual mode to shift down when I want to, the manual mode select the maximum gear level that will be used, if you select the 5th, it will not shift in 6th, so you could downshift to 5th or 4th as you want, we don't need that the computer does it until running the motor to 4000-5000 rpm as it downshifts in 4th when the speed is over 100 km/hr(65 MPH)
 

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When going downhill, think of your accelerator as a messenger to the computer (not the fuel injectors).

Foot ON accelerator (even very lightly) = "I want to maintain my speed, or go faster."

Foot OFF accelerator = "I don't want to go faster than my CURRENT speed."

If the computer knows that you don't want to go faster than the speed you were going when you removed your foot from the accelerator, and you are gaining speed, it will downshift to initiate engine braking.

On steep declines, enjoy the engine braking and be happy that you are not overheating your brakes.
This doesn't work - only accelerates in 4th gear
 

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Not that far off really. I found the posts useful and realted. If all you wanted was an answer to the OP’s origional question- the answer is no.
 

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turn off cruise control, even if not engaged seems to make them downshift to hold lower speed
 
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