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Old 12-10-2017, 06:45 PM   #1
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down shifting

I'm hoping someone can answer this:
When driving our Jayco Precept 31UL and cresting a hill the unit downshifts a couple of gears and the RPM jumps up to 4-5 thousand RPMS. Is this normal - no one seems to have an answer - I talked to Ford and they couldn't answer it either. They told me to bring it in and they would drive it - and if it happened they could address it. It doesn't happen all the time, but would love to get this fixed, if it is not normal.
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Old 12-10-2017, 07:22 PM   #2
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Sounds like it has some sort of engine tune or feature which allows the gas engine to behave more like a diesel with an exhaust brake.

One rule of thumb when driving is whichever gear is used to get up the hill should be the same gear used to get down.
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Old 12-10-2017, 09:15 PM   #3
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Check your Ford manual page 34 (on my manual) its called: Forced Downshifts.
If you drive with the cruise control on it will downshift to very high rpm's if you go downhill. Keep in mind that it is doing this to keep the speed programmed. Forced Downshifts is on also if the tow/haul feature on or off. It is a feature of the transmission. There are many posts in the internet about that. google: ford Forced Downshifts motorhome
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Old 12-10-2017, 09:39 PM   #4
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Mine does this also, iím sure they all do. Drives me crazy seeing the RPMís over 4k screamimg like that.
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Old 12-10-2017, 11:56 PM   #5
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Area you using the Tow/haul mode when going thru hills?
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Old 12-11-2017, 07:13 AM   #6
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Tow haul doesn't effect the forced downshift. It's to save the brakes on long steep downgrades... the V10 was designed for high RPM's, don't worry about it.

We used tow haul on the 5 speed tranny in the old motorhome, but we've never had to use it with the new motorhome, as it has a 6 speed tranny.
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Old 12-11-2017, 12:03 PM   #7
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I looked at some other forums on RV towing especially gas vs diesel posts. It seams the Ford V10 is made to run comfortably above 4000 rpm and can run at 5000 rpm when climbing with a load. You might check out those resources. I found them helpful.
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Old 12-11-2017, 02:22 PM   #8
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We drive mountain passes quite frequently and there is a workaround for this. I keep my 35S in tow haul mode while ascending the grade. As we descend and the transmission drop gears I just take it out of tow haul mode and it will upshift right away.
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Old 12-11-2017, 04:09 PM   #9
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Quote:
Originally Posted by Vicr View Post
We drive mountain passes quite frequently and there is a workaround for this. I keep my 35S in tow haul mode while ascending the grade. As we descend and the transmission drop gears I just take it out of tow haul mode and it will upshift right away.
I had posted on this subject a while back. 4000 rpm is unnerving, is good to hear that it is ok. This tow haul workaround is something I’ll definitely be experimenting with the next time I’m in the mountains. I gather the V10 has electronic rev limiting. Is the limit 4000 rpm? I can’t recall whether or not i’ve seen anything higher than that. Would explain why the tach shows no red line, I suppose.
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Old 12-11-2017, 04:49 PM   #10
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5 star tuning

Many people are unhappy with the V 10 engine and transmission combination - I hear that 5 Star Tuning can make it much better ( no personal experience )
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