We have the Allison HD4060R transmission. Prior to today when downshifting to 4th or 3rd gear to climb a hill or mountain, I would walk back up through the gears one by one when back on a level plane.
Today I climbed a hill and at the top of the hill we were back on flat land. So I pushed the D button and the transmission smoothly shifted back into 6th. I did not know I could do this.
Hi George, I can assure you, there are more learning curves ahead, it is never a dull day for me, Maybe it is due to my bad memory, but I keep finding new gadgets and gidgets every day I am in the coach snooping around. I feel I have found some things a few times before but can not recall but they seem familiar :)
You need to try on a Phenix, that will keep you real busy for a long time with the gadgets etc :))
The old saying about a box of chocolates ;D
Yup, the up and down arrows, D and economy/power mode can all be selected as often as desired and at any speed desired. Said another way, pushing the down arrow 5 times at 60 MPH will do no harm. The Allison ECU understands that command to be: "Please downshift one gear at a time as soon as it can be done in each gear without overspeeding the engine."
Brett
I realize this discussion is for a HD4060 transmission. But does this also apply to an Allison MD3060R transmission?
Thanks, Brett. That is also good to know.
George,
Both 3000 and 4000 series dating from 1993 are basically bomb-proof when it comes to driver input.
They are programmed with maximum permissible engine RPM, etc and will NOT do/allow the driver to do anything harmful to the drivetrain.
And as one learn to use the shift pad, the options are great-- particularly for those of us who want control over what happens (vs just putting it in "D").
Even in rugged mountain driving, I leave it in economy mode and then use the down/up arrows to select the correct gear. YES, a good driver is much superior to the Allison ECU in choosing the correct gear. After all, the Allison is VERY REactive-- because of the momentum of the heavy coach, it really only "sees" what happened 1/4 mile behind you. We, as drivers can be PROactive-- seeing that we are going from a steep downgrade to a short 8% upgrade and gear accordingly.
Brett Wolfe
Brett,
More good info. We have been not using Economy when in foot hills. But it sounds like we can eke out a little more economy by leaving it in and just selecting a gear or two lower as appropriate.
Both Sandy and I have learned so much here.
George,
If you read your (fill in the blank...) Caterpillar, Cummins etc operators manual (actually all but the DD two stroke engines), the most economic way to climb a grade with a modern turbo after-cooled diesel is at or just above peak torque RPM-- even at high throttle settings. And if you open you window on a grade, you will hear the owner operated 18 wheelers operated just that way. Ya, the 18 wheelers who don't pay their own fuel bill may still have them wound up to the governor-- but as I said, they are likely not buying the diesel.
The Allison economy mode basically means that the Allison engineers read the engine manual and therefore offer you the choice of "most economic" (economy mode) OR "I don't care how much diesel it takes, I don't want to slow down 1 MPH on that hill" (power mode).
No right or wrong answers-- but you do have the choice of what the Allison does.
Brett Wolfe
Brett, you excluded the DD 2 strokes, why? Is there something I need to know about getting the best economy out of my DEDC?
Kent,
Unlike the modern four stroke turbo diesel, the DD two stroke should NOT be lugged (run at WOT at peak torque RPM).
Your engine likes its RPM's. Totally different technology.
BTW, the most fearsome DD I have ever encountered was on a Mexican built Sultana bus in Mexico in the early 1970's. The largest bus I have ever seen-- tandem FRONT axles as well as drive and tag!
DD 12V71 (yes, that is 12 cylinders) with 10 speed manual transmission.
Cruising speed 145 KPH. That is just shy of 90 MPH! And with the straight pipe exhaust, you KNEW it was coming.
Brett Wolfe
Is there any way to improve mpg with the DD two stroke? I was pretty well spoiled by the 9 to 10 mpg on my U225.
Put it in neutral and push it...
I know this is a very dumb question, but how is the economy or power mode selected? I recall the transmission has the D, R and the up and down arrow buttons to select different gears when in drive. But I don't recall seeing power or economy buttons.
I am learning a lot here also. Thank you.
Dave, George suggested my wife push in a PM he just sent. Neither suggestion is going to happen.
There is a button on the shift pad that says "mode". The default setting (i.e. every time the ignition is turned on) is POWER mode. Push the button and it goes to ECONOMY mode and the little light comes on. Push it again and you are back to POWER mode.
Brett Wolfe
Ah...Thank you so very much!! I greatly appreciate this information!!
I thought that was how it should work on our 99 U270, but the light on ours only lights up when it's in power mode and at initial start of engine, it's in Economy mode. Doesn't bother me at all, since I want to be in Econ mode most of the time anyway, but I'm guessing that's an Allison-changeable option in the TCU.
Brett, does your transmission on your 93 have modes? A better question is does my U300?
Kent,
The mode button applies to all Allison 6 speed electronic transmissions-- 3000 and 4000 series including ours.
I believe the U300 has the old-style hydraulic 4 speed Allison. If so, no, it doesn't apply to you or the U225, neither of which were fit with the electronic transmissions.
Brett Wolfe
Wow, we learn something every day. I never knew I had an economy mode either.
George S - I find that shocking that with 450 horses you ever have to shift down. I just got back from a trip to Washington state, through the Montana and Idaho passes on I 90. I was down to 4th gear and 45 mph and all the time I was thinking - if I had 450 horses instead of these measly 300 I wouldn't have to be poking along here!
Gayland,
It is not how many horses are in the year stable, it is the gearing on the treadmill that makes all the difference in the world. On one of our early ventures into the mountains of the front range of the Rockies we did not downshift and ended up over heating the engine. Climbing a very long and very steep mountain grade with lots of switchbacks, single lane in one direction we luckily found an area to pull off. We now are very pro-active about downshifting.
George Hatfield sums it up best: use 3rd gear in the 30s and 4th gear in the 40s. To that we add 5th gear in the 50s when going up steep grades if we go that fast.
George,
While higher RPM IS the short-term solution to rising engine temperature, it may also be an indicator that you need to clean the CAC (Charge Air Cooler) and radiator.
Think of the dirt deposited on the side of your coach when you drive in rain. Now, picture the many thousands of cubic feet of that same dirt and water ladened air that is sucked into your cooling system. When that muddy water hits the hot metal of the CAC and radiator, some of the water evaporates and leaves the dirt deposited. This dirt slowly starts blocking the air passages of your cooling system.
So, anytime your coach is really dirty, it is a good idea to open/access the CAC from the side of the coach (from bedroom on rear radiator configurations) and with a garden hose nozzle systematically clean the fins. If there is any oily deposit, use a little Dawn as well. You will be shocked at what you flush out.
Brett Wolfe
Do any of you find much improvement in the milage in Economy mode vs power? When should you and when should you not use the Economy Mode?
Thanks
Mike
Here is a a good write about the Mode Button.
http://beamalarm.com/Documents/allison_mode_button.htm (http://beamalarm.com/Documents/allison_mode_button.htm)
Mike,
There can not be any standard answer here, as it is highly dependent on where you are driving. On flat ground-- say I-10 in Louisiana there is no difference in MPG, as your transmission is not down/up/down/up shifting whether in economy or power mode. Continue west on I-10 to the Texas hill country and it can make a significant difference.
Depending on engine and GCW, in the hill country your transmission may downshift on each grade from 6-5, then back to 6 after you crest the hill. In economy mode, you are able to climb all/most of these grades in 6th gear. WOT in 5th gear burns a LOT more fuel than WOT in 6th.
Brett Wolfe
Thanks Barry,,,,,,,just what I was looking for....Your right, great writeup!!
Thanks Brett, I got 'cha....
Mike
First question: Yes. Maybe .5 MPG
Second question: all sorts of answers available. Some earlier replies to this topic suggest being more pro-active.
When in hills/mountains we do this -- 2nd gear 20s 3rd gear 30s 4th gear 40s
Thank you very much for this write up. It is very informative.
My display says "mode on" when I press the mode button. I have been told that the default may be power or economy mode on startup, depending on what the factory programmed?
David,
That is correct. The default mode is part of the Allison programming and can be set to the OE's specs-- with either mode being the default mode.
BUT I have never seen an RV with anything but POWER mode as the default mode. That means you have to push the mode button each time you start the coach if you want to select ECONOMY mode.
Brett Wolfe
My transmission default at startup is economy. I have to press the button to get power mode. Shift control panel says power on it next to the led to indicate the the power mode is on.
Mark
To confirm which mode you are in:
In POWER mode, accelerate from 0-50 or so at WOT (Wide Open Throttle). Note highest RPM in each gear before it up-shifts to the next gear.
Repeat in ECONOMY mode.
The "real" economy mode will show lower RPM's before upshifting to the next gear.
Were it me, I would choose ECONOMY mode as the default as well-- heck that would save me one "button push" each time I start the engine.
Brett Wolfe
Brett,
I already verified that it is defaulted to economy. It came that way when new. The control panel is labeled "POWER" next to the led for the mode switch instead of reading "ECONOMY". Led illuminates when I press the mode button to put it into the power mode. I can take a picture if you would like.
Mark
Ours (99 U270) works the same way - starts in economy mode, but the LED is off. The button is labeled "Economy". Press the "Economy" button, and the "Economy" LED lights up and it's in Power mode. It's definitely in Power mode. Revs right up, shifts down right away when you go up a hill or step on the loud petal, etc.
Just read a TSB summary in http://www.compnine.com/research.php?tsb=1&tsbmake=FORETRAVEL&tsbmodel=FORETRAVEL&tsbyear=9999 (http://www.compnine.com/research.php?tsb=1&tsbmake=FORETRAVEL&tsbmodel=FORETRAVEL&tsbyear=9999) (ref in a msg from Barry Leavitt (Barry and Cindy)
That states:
19990313 103100 POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM, PCM) 20000531 THE TRANSMISSION ECU IS REPROGRAMED FOR THE MODE ON TO BE ECONOMY NOT POWER. ALL 3066'S PRIOR TO THISMODE IS POWER.
So sounds like the switch function got reprogrammed in the Allison TCU sometime in the 1999/2000 period.
Mark and Dave,
Thanks very much for the update and TSB reference.
I knew earlier ECU's were programmed with POWER as the default mode.
Glad to see the newer ones default to ECONOMY.
Most SOB's never made the switch.
So, my write-up on the Mode Button in Barry's link applies as is to earlier coaches and one has to understand that on newer coaches you are in ECONOMY mode each time the engine is started unless you push the mode button.
Brett, My 2003 starts in "power mode" and I always put the mode button on as the extra step when starting to put it in Economy mode.
Barry,
OK, that may suggest that everyone do a simple test to determine how their Allison ECU is programmed-- i.e. whether the default mode is POWER OR ECONOMY.
To confirm whether your default mode is POWER or ECONOMY:
Start the engine. Do NOT push the mode button. Accelerate from 0-50 MPH or so at WOT (Wide Open Throttle). Note highest RPM in each gear before it up-shifts to the next gear.
Push the MODE button on the Allison shift pad.
Accelerate from 0-50 MPH or so at WOT (Wide Open Throttle). Note highest RPM in each gear before it up-shifts to the next gear.
The transmission will up shift at lower RPM's in ECONOMY MODE.
Brett Wolfe