Class C downshifting ?

That V-10 is revving because that's where the horsepower is. I've climbed grades at 4,000 rpm and that V-10 is happy there. Turn up the radio and let it rev.

Are you using cruise control?

If you aren't doings so already, try engaging tow/haul. It will still downshift, but the shift points are a little more appropriate for a heavy vehicle and it should hold in gear a little more reliably, both going up and down.

As others have said, though, the V10 needs to rev quite a bit, particularly for a truck engine, to generate power. If it didn't downshift and rev up it would be quite a dog on the hills. It's just the nature of the beast. Although it may sound like it's going to shred itself to pieces, the engine is quite capable of running at the higher rpm's for reasonably long times without trouble.

Some people here have put in four star tunes and reported good results; among other things, they can tinker with the shift points some.

(Another way to improve this would be to get a newer motorhome with the six speed transmission, which has somewhat closer and more evenly spaced gear ranges. I think there are also some aftermarket overdrive/gear splitter units available that should help a lot...for a price.)

If anyone finds a way to manually control the Ford 6 Speed Auto Transmission that came in my F53 Chassis, I would gladly purchase it. Any aftermarket engineers out there looking for a challenge? My Diesel Pusher with the 6 Speed Alison had a control pad that would allow me to put it in Drive and let the onboard computer do it's thing or I could manually shift or hold gears. This option gave me the best of both worlds. My Ram Pickup allows the same thing. Please... anyone??? JH

Search 5 Star Tune on this forum and irv2.com/forums. I have it and it made a dramatic difference on my 6.8L V10 with five speed transmission. They also reprogram diesels.

Take a look at the power band for your engine. Do some reading about it and then get a tuner and control your shift points. Most engines are much happier in a lower gear and a slower speed when pulling hills.

jstrong499 wrote:

Like to hear folks dealing with the same thing
Thanks,
Jamie

You can minimize that downshifting by:

Being sure you are NOT in the tow/haul mode.....
And NOT using the cruise control.

You can minimize it a bit by "charging the hills" and by letting your speed drop slightly going up.

But you can't eliminate it completely. That's the way it is designed to work.

While it sounds like it's going to fly apart, it probably doesn't rev about 4K and will be perfectly fine.

My 450 did that when pulling a trailer, even going over overpasses on the Interstate sometimes. My Workhorse A does it some too.

DrewE wrote:

Some people here have put in four star tunes and reported good results; among other things, they can tinker with the shift points some.

I did that and it helped with the downshifting some.
But when it stayed in top gear and pulled hard, the engine vacuum went down enough that the A/C air flow got squirrely.

The {late model 2 valve} V-10 makes max torque of 420# at 3,250 rpm and max HP of 305 at 4,250. You can run at 4K+ all day without harming that beast of an engine but you will burn a ton of fuel.

At max torque of 3,250 my fully loaded C, towing my motorcycle in the 10' cargo trailer (bike and trailer weigh 2,220} will climb almost any 6 percent grade at 55 without excessive noise and with reasonable mileage {been averaging 9ish for years}. Rare indeed is the 6 percenter that lasts more than 10 or 12 miles so you will be over the hump so to speak, in just a few minutes.

Tow haul is your friend and unless you're running very light, on the flat or a slight downhill you should utilize it for optimum performance as it resets the shift points. On steep downhills, it provides engine braking without burning a drop of fuel, saving your brakes. It also will keep your transmission 12 to 20 degrees cooler extending its life.

To get the best out of this fine engine just put your foot in it as needed and use your Tow Haul.

:C

Desert Captain wrote:
The {late model 2 valve} V-10 makes max torque of 420# at 3,250 rpm and max HP of 305 at 4,250. You can run at 4K+ all day without harming that beast of an engine but you will burn a ton of fuel.

At max torque of 3,250 my fully loaded C, towing my motorcycle in the 10' cargo trailer (bike and trailer weigh 2,220} will climb almost any 6 percent grade at 55 without excessive noise and with reasonable mileage {been averaging 9ish for years}. Rare indeed is the 6 percenter that lasts more than 10 or 12 miles so you will be over the hump so to speak, in just a few minutes.

Tow haul is your friend and unless you're running very light, on the flat or a slight downhill you should utilize it for optimum performance as it resets the shift points. On steep downhills, it provides engine braking without burning a drop of fuel, saving your brakes. It also will keep your transmission 12 to 20 degrees cooler extending its life.

To get the best out of this fine engine just put your foot in it as needed and use your Tow Haul.

:C

X2 We also have the 5 star tuner and its made a very large difference. We routinely tow a 3200 lb. car or 2 Harleys on a trailer and the RV gets a workout. Easy 55-60 MPH up those grades unless a truck/traffic slows us down. Also improved the shifting. Just as aside we also gained 1 MPG.

Dave