E450 W/Cruise on - downhill downshifting - aggravating !!

hayseed · 01-24-2011, 07:51 AM

Aggravating !! We're currently in a Forest River 283TS Lexington with the E450 chassis and Ford V10. When using cruise control, if a hill is steep enough, the 'all knowing' computer will downshift the tranny in an attempt to maintain consistent speed. Sometimes the engine will hit 4K or 5K RPM ... can't be good !!
QUESTION: Is there any way to prevent this (other than not using cruise control or turning it off on downhills) ?? Maybe one of those Bully Dog engine tuners ??
Anyone else have this aggravation ??

subford · 01-24-2011, 08:35 AM

Just push the button on the end of the shift lever. This will take you to 3rd gear instead of 2nd gear.
And do not use the speed control when going down a steep hill.
Do not touch the brake as this will unlock the TQ.
Then you will then only have TQ without its clutch to slow you down.

By the way only GM products have cruise control, it is a brand name, FORD has Speed Control.

frankdamp · 01-24-2011, 08:41 AM

That's the way it's supposed to work. It's just doing what you would do on a manual tranny to get extra engine braking going downhill.

Many different automatic transmissions have it. It's called "Grade Logic". It's the same computer routine that will hold a lower ratio when you're climbing a hill to prevent hunting back and forth.

My '85 Camry had it, so did my 95 Accord and 95 Odyssey. I haven't noticed it on the F53 9an '02).

hoppers4 · 01-24-2011, 10:05 AM

The only way I know of to prevent this from happening is to turn off cruise control. HOWEVER, when you start braking to slow down (depending on how much you brake), the transmission logic will still dictate a downshift in an attempt to prevent overusing the service brakes.

Tom-NC · 01-24-2011, 10:14 AM

Hayseed,

When going down hill NEVER use cruise control. Push button to take you out of cruise and then depending on percenrage of grade manual shift to 2nd to take you down the hill and if you run too fast then gently put on the brakes and release.

This way you have control of the vehicle. I was always taught to go down a hill in the same gear you have to climb it.

One final thing when going up a hill take it out of cruise and use the accelerator and if you go below 45 mph downshift to the next lower gear, this way you are maintaining your speed as well as helping the transmission. Never try to climb a hill in overdrive.

Enjoy!

subford · 01-24-2011, 11:07 AM

Using 2nd can over rev the engine. Push the button on the end of the shifter to go to 3rd and then if you get the speed low enough you can go to 2nd.

OD is 4th gear.

Izzyblueye · 01-25-2011, 05:45 AM

You have just received very good advice.

Tom-NC · 01-25-2011, 08:02 AM

Subford,

That statement may be right in a Ford, however in my Workhorse w/ Alison Transmission if the engine revs too high it atuomatically upshifts. Also if you upshift to 3rd then you are defeating the purpose of the tranny holding you. Like I stated previously if you tap the brakes a little it will keep the speed down and there will be no over revving.

I had 2 Fords with 460's and it never revved too high but just held the coach back. I assume the v-10 does the same thing.

Ultimately there is a lot of common sense going down hill, in fact if it is too high than stop at the top and put it in low gear or better yet you shouldn't be on it.

Enjoy!

frankdamp · 01-25-2011, 10:13 AM

There's a very big ratio change between "D" and "2" on the F53 transmission. There's no selector for "3". Using the O/D pushbutton will give you an interim step.

The V10 does rev higher than the older big-block V8s, so 4000 rpm isn't unusual.

rvten · 02-28-2011, 09:23 AM

Never use Cruise Control going up/down hills. Turn on Tow Haul when going down a hill. When you tap the brake pedal. Trans will down shift as needed. Saves the brakes.