V10 Shudder/vibration Climbing on Cruise Control

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Kirk

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Sure, but don't you think you have better control over it with your foot?
I have found that good control requires the use of the gear shift and the brain as well as one's foot. If the transmission is hunting it is time to get out of D and find a gear to stay in. If that only means no OD, then it might even be OK in cruise, but those decisions are where the brain comes in. With any modern vehicle that has a tach it is very easy to know what is happening.
 

DonTom

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""Using cruise control while driving through hilly terrain could cause the system to force multiple transmission shifts which could lead to overheating of the transmission fluid and premature component wear," said Stephen Leroux, automotive professor at Centennial College in Toronto."

See here.

-Don- Crescent City, CA
 

Mark_K5LXP

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Some cruise controls are better than others in terms of their anticipation and anti-windup. I've had cruise in previous cars that would go between coasting and floored to maintain some very narrow range of set speed. More contemporary ones I've seen are less "rigid", allowing a small drift in speed based on some calculation of rate of change, gear and loading. For my RV at least and likely most, there's limited power for a cruise to work with to maintain a set speed without downshifting. Manually you may not notice or care dropping 5mph going up a grade but the cruise it will suck the pedal to the floor to maintain the set speed. A consequence of that is a downshift, so while it's "normal" for a tranny to do that, with cruise on the potential is there for a lot of downshifts. A transmission that's getting downshifted under the load of a grade is getting hammered, so in my view it's not "good" for it. I've used cruise on some long flat stretches but it doesn't take much of a grade to force a downshift so that's when I leave it off, and let the vehicle speed up and slow down within the torque limits of the gear I'm in. I'm not in that big a hurry.

Mark B.
Albuquerque, NM
 

Babe2201

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""Using cruise control while driving through hilly terrain could cause the system to force multiple transmission shifts which could lead to overheating of the transmission fluid and premature component wear," said Stephen Leroux, automotive professor at Centennial College in Toronto."

See here.

-Don- Crescent City, CA
Well if what he said was true over half the auto transmission in the country would need to be replaced or rebuilt next year. When that happens I will believe him.
 

DonTom

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Well if what he said was true over half the auto transmission in the country would need to be replaced or rebuilt next year. When that happens I will believe him.
Doesn't work like that. Perhaps many trannys last less than 100K miles for that reason which would normally last 150K miles or whatever. Who would notice the difference? Just because you cannot notice the difference in how long your tranny lasts doesn't mean there is no difference.

BTW, the same goes for using OD in the hills. It can cause too much shifting.

Probably it's all okay with CVT's but I hear they never last long anyway. I have never owned a vehicle with a CVT so I cannot say one way or the other if it causes any issues, but probably not, as there is not real gear changing, just a belt moving around, IIRC.

-Don- Crescent City, CA
 

Babe2201

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Doesn't work like that. Perhaps many trannys last less than 100K miles for that reason which would normally last 150K miles or whatever. Who would notice the difference? Just because you cannot notice the difference in how long your tranny lasts doesn't mean there is no difference.

BTW, the same goes for using OD in the hills. It can cause too much shifting.

Probably it's all okay with CVT's but I hear they never last long anyway. I have never owned a vehicle with a CVT so I cannot say one way or the other if it causes any issues, but probably not, as there is not real gear changing, just a belt moving around, IIRC.

-Don- Crescent City, CA
How many trannys have to be replaced with less than 150K? What you hear about the CVT transmissions is really not true. I have a lot of customers with them that have held up very well.

I am still not sure how using cruise control is going to cause it to shift more and ruin a tranny. If anything a driver losing speed and then trying to make up for it would cause it to shift more.
 

Babe2201

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Oh, so that is it. You're in the tranny business so the more failures you see the better for your business! ;)

-Don- Crescent City, CA
Nice try but I am in the tire business but I talk to my customers about their vehicles. I appreciate you calling me a crook.
 

DonTom

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Can you keep anywhere near a steady speed
A steady speed isn't the issue. Excessive shifting is the issue. And we can control that better with our accelerator pedal.

The cruise control trying to keep a steady speed IS the issue as it often does that by auto-shifting and that is what we should be trying to reduce.

-Don- Crescent City, CA
 

Babe2201

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A steady speed isn't the issue. Excessive shifting is the issue. And we can control that better with our accelerator pedal.

The cruise control trying to keep a steady speed IS the issue as it often does that by auto-shifting and that is what we should be trying to reduce.

-Don- Crescent City, CA
How is it going to shift more when the vehicle is automatically keeping a steady speed?
 

Babe2201

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In the hills? A lot! That is how it keeps the steady speed when the engine doesn't have the power for the higher gear in the hills.

-Don- Crescent City, CA
We will have to agree to disagree on this one. I have used cruise in some pretty hilly areas and did not feel the vehicle shift any more than it would have if I was not using cruise control. I have talked to mechanics about vehicles with known transmission issues and not one of them have ever said that it was from people using cruise control on hills.
 

Mark_K5LXP

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did not feel the vehicle shift any more than it would have if I was not using cruise control.
If you're modulating the gas to hold a steady speed then this is plausible, because your foot is acting the same as cruise would. The premise of the discussion though is to *not* mimic cruise, letting the speed move up and down and staying within the power limits of the current gear so downshifting is not required.

Mark B.
Albuquerque, NM
 

Kirk

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The premise of the discussion though is to *not* mimic cruise, letting the speed move up and down and staying within the power limits of the current gear so downshifting is not required.
And by watching the tach & gearshift to keep in the power range of the engine as well as the foot and the brain. Some people need to read the owner's manual of their RV chassis. :unsure:
 

DonTom

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steep grades I would agree but no hills at all??
I think of "hills" as between my Auburn house (1.4K' elevation) up to Donner Summit (7,240' elevation). I will only use a cruise control in my EVs on those hills.

I would put it this way, as long as the tranny isn't shifting back and forth too much, you're probably okay. And that depends on the hills.

Of course, a slight hill won't be a big issue if it isn't causing repeated shifts.

-Don- Dunnigan, CA
 

crawford 111

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I guess I heard it all my C class and my A class can't be driven in cruse control. On hills and curves being in smoky Mnts leaves me not using it much LOL. AT 50 years never a accident and not a transmission repair . Looked in Ford book say not good in rain or snow.
 

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