1cowboy
Oklahoma
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Okay dummy here asked this before & forgot to print out responses!
Have 2002 Dutchmen (bought new) w/Ford E450 V10 Triton. Tow '98 Jeep Wrangler w/stuff. Sorry don't know transmission ratio. No tach...one of the stupid things not on this rig. Use OD often & even in hills (not mountains) but not cruise. A whole lot of (up)shiftin' goes on under this driving condition. Sometimes even in modest rises on road. Run under 65 mph. Could this be too slow and should I kick it up to 65 (don't think it's safe to go much faster)? Might this also improve MPG? Should I not use OD? Once I clear hills of southern OK and get further down into TX on my way to wintering in South Padre Island, terrain flattens out and this situation doesn't exist & I can even use cruise. Thanks...again!
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j-d
Sunny Florida USA
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Our 2002 setup is very sensitive on Cruise, will downshift to go over an interstate overpass on otherwise flat ground. I get much less down/upshifting if I drive without Cruise.
I've found that running faster does in fact eliminate some of the downshifts. If you can't run faster safely and legally, and then the transmission starts "hunting" (frequent, repeating down/upshifts) then you'll need to Cancel OD. The PCM (powertrain control module) is programmed to not let you lug in OD.
God Bless, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100
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Goldencrazy
madison wi
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I have an '04 V-10 on 28 FT MOHO towing a lighter smart car. I use the tow haul option when I get in hills and mountains which pull me down to 50-55. Cruise control is very sensitive so in hills I turn it off. I was of the mind that when I tap the button and light comes on I was disengaging the overdrive and going to a 4 gear situation which works best in hilly terrain. On more level areas I turn off the light and it allows for a fifth gear which is the "normal" state.
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garym114
Texas
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Joined: 07/24/2006
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Is this the one you lost?
What gear?
Get a Digital Multimeter and Learn How to Use It
2000 Sea Breeze F53 V10 - CR-V Toad
Dawson Creek - Start of Alaska Highway
Don't Forget - USS Liberty, June 08, 1967
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Pangaea Ron
Anacortes, WA, USA
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j-d wrote:Our 2002 setup is very sensitive on Cruise, will downshift to go over an interstate overpass on otherwise flat ground. I get much less down/upshifting if I drive without Cruise.
I've found that running faster does in fact eliminate some of the downshifts. If you can't run faster safely and legally, and then the transmission starts "hunting" (frequent, repeating down/upshifts) then you'll need to Cancel OD. The PCM (powertrain control module) is programmed to not let you lug in OD.
Good response, and matches my experience.
2002 Triple E Senator 28C XL
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1cowboy
Oklahoma
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garym114...YES! That's the one. Thanks for thinking for me! However in that discussion there was a lot of back & forth about cruise as there is in this one. Let me repeat: I DON'T USE CRUISE IN THE SITUATION EXPLAINED. Just wanted to know if maybe I'm lugging the engine & need to speed it up a bit. And yes, I often do take it out of OD when encountering a hill...but sometimes I'm a bit slow reacting to the upcoming hill. I have also been told by old timers (no disrespect meant) smarter than I am to let the transmission do what it's supposed to do; if it upshifts, downshifts or whatever, it's working. Many of you have said the same. Thanks for enlightening me...again.
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dceggert
SE Michigan
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Here is how to think about it...if the transmission downshifts going up a grade it is exactly like pushing the O/D Cancel button manually. It will do this when the load on the engine reaches a certain level and the speed is not keeping up to what is being demanded either by the pedal position or the cruise control signal. If the transmission is continuously upshifting and downshifitng in this condition then you are at the magic point where it is having trouble staying in either gear. Pushing the O/D Cancel holds it in 4th with the 5R100. The only thing that happens is it does not keep bouncing back and forth.
As for wondering if faster would be better to try to keep the MH in 5th for better FE, remember that faster is more drag too.
The 6.8L V10 makes a lot of power at elevated RPM. As a result, the transmission needs to first slip out of torque converter lock to elevate the engine RPM's. If that is not enough to maintain speed it needs to downshift a gear to elevate the RPM's even more.
Those of you that may be used to the old 7.5L with the E4OD will think the 6.8L is downshifting earlier and it is. The old 7.5L out-torques the 6.8L up to about 3000 RPM and then the 6.8L pulls handily away. What that means in the long run is the 6.8L will be downshifting before the 7.5L used to in the same situations.
If the shifting is harsh and elevated speeds do not help then pushing the O/D Cancel may smooth out your nerves a bit. Other than that the shifting is not bad for the vehicle...it is doing what it is supposed to do.
regards,
Dan
1992 Coachmen Leprechaun 265RF
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smkettner
Southern California
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Sounds like it needs one set lower gears in the rear. Otherwise first downshift lock out OD and set the cruise.
2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
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tatest
Oklahoma
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Your E-450 has 4.56:1 rear gearing, for 225/75R16 tires. This puts the rpm near the bottom of the torque curve for 65 mph cruising, in overdrive. There is not enough HP at that rpm for much more than dealing with level ground and still air.
Much of a headwind, or a slight grade, the ECM will shift down to direct drive (3rd gear in the 4R100, 4th in the 5R110). This puts the rpm up around 4000 for about 1/3 more power at the same torque, but still short of the horsepower peak. There is about 1000 rpm left on the flat part of the torque curve, to let you run up to 70-80 mph for passing, before power falls off.
I also miss the tachometer telling me what's going on, but I've also driven this chassis several hundred miles with the 5-speed and the tach, and find the tach is not really useful because there is nothing you can do shifting manually. The top three gears are in 70% steps, there are no intermediate ratios for fine tuning, and the ECM will put the transmission in whatever gear most closely satisfies your power demands.
I don't think there is enough extra power at 65 mph or 70 mph, to keep the transmission from shifting down on slight grades. Compared to 60 mph, there is not that much more RPM. If anything, trying to run slightly faster may make the transmission shift down more often.
If this really bothers you, one solution is an auxilary transmission like the Gear Vendors, which gives you an 80/20 underdrive or overdrive, for slightly closer gear spacing than the stock transmission.
I would like to have this engine come with a close-ratio six-speed manual. The automatic, before it shifts down, will unlock the TC for another 300-500 rpm, which helps to fill the gaps, but it is not the same as having more gear ratios to work with.
Direct drive (whether it is 3rd or 4th) at 60-70 mph isn't going to hurt anything. The engine can run at 4000 rpm all day, and that's where the older, slower big-block V8s ran on these trucks before they started giving us an overdrive for better economy under light load conditions.
Tom Test
Itasca Spirit 29B
2001 Ranger Edge
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Kamphiker
South Florida (this 'aint paradise anymore)
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Suggest you get a scanguage
you will then have a TACH plus many other guages (Trans Temp.)
It will help you find the "SWEET" spot in various driving conditions.
2006 Winnebago Outlook WF324V
2009 Honda CR-V 2wd TOAD ......Campgrounds in the Smoky Mountains NP
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