ALLISON TRANSMISSION MODE BUTTON

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ALLISON TRANSMISSION MODE BUTTON

March 14, 2020, 08:14:08 pm

First, I must say I have read Bretts article and find it very informative- i.e.-ALLISON TRANSMISSION MODE BUTTON, BY BRETT WOLFE, F252125. here is link: "Mode" button on Allison
Thank you very much Brett.
I am writing because, while driving my 2004 U320 with cruise control on, the tranny on sure seems to act like its in the performance mode only after I push the mode button and the red light comes on. It downshifts going uphill much sooner with the red light on in comparison to when it took a lot longer and lost more rpm with the mode light off. I have driven from Arizona to Virginia over the last 3 days and have monitored each mode. Are there different set ups out there, some in performance mode when red mode light is on and some in economy mode when red mode light is on?

Thanks to all

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #1 – March 14, 2020, 08:21:37 pm

Mine seems to be the opposite as what others are. As I understand it. The default is supposed to be econ mode which is mode 1. But on mine, Mode 1 has the trans down shifting on the slightest upgrade. If I change to mode 2 which is supposed to be sports mode. It holds the gear longer before down shifting.

I would imagine that is a programmable thing.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #2 – March 14, 2020, 08:48:45 pm

cdm,

The "Mode" button can be set up either way. Sounds like yours was changed to default to "Economy" and when you push "Mode" it will go to the performance mode. If you want it changed back you will need to have an Allison shop hook up there computer and change the ECM unit. Takes about 5 minutes to change.

Mike

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #3 – March 14, 2020, 09:31:19 pm

Mine is the same. It defaults to Economy on startup and goes into power mode when I select it.

Mark

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #4 – March 14, 2020, 09:52:44 pm

Mine is performance first.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #5 – March 15, 2020, 09:08:32 am

Mine defaults to power mode on start up. I have a text box on my VMSpc with ECON when I press the mode switch to verify I'm in economy mode.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #6 – March 15, 2020, 09:17:06 am

Yes, either economy or performance mode can be programmed as the pre-select (what happens each time the key is turned on). Most Allison ECU's for RV's have performance mode as the pre-select, most trucks economy mode.

Any Allison dealer can determine by plugging in their tester. And, very easy for them to program it either way in less than 10 minutes.

Also easy for you to VERIFY.

Next time you are driving, engine warmed up, do the following in each mode:

Accelerate from a stop to, say 50 mph at WOT (Wide Open Throttle).

Note max RPM in each gear.

You will note quite a difference in RPM before upshift-- higher in power mode.

File that away in your brain for future reference.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #7 – March 15, 2020, 09:21:13 am

Quote from: wolfe10 – March 15, 2020, 09:17:06 am

Yes, either economy or performance mode can be programmed as the pre-select (what happens each time the key is turned on). Most Allison ECU's for RV's have performance mode as the pre-select, most trucks economy mode.

Any Allison dealer can determine by plugging in their tester. And, very easy for them to program it either way in less than 10 minutes.

Also easy for you to VERIFY.

Next time you are driving, engine warmed up, do the following in each mode:

Accelerate from a stop to, say 50 mph at WOT (Wide Open Throttle).

Note max RPM in each gear.

You will note quite a difference in RPM before upshift-- higher in power mode.

File that away in your brain for future reference.

Have you ever heard of the modes themselves being reversed? My mode 1 (default) is actually the performance mode instead of performance being mode 2 as everyone else.
Not a big deal. Just more curious than anything.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #8 – March 15, 2020, 09:30:36 am

Quote from: bigdog – March 15, 2020, 09:21:13 am

Have you ever heard of the modes themselves being reversed? My mode 1 (default) is actually the performance mode instead of performance being mode 2 as everyone else.
Not a big deal. Just more curious than anything.

YES, that is what I was describing. Either can be the pre-select mode (the one that comes up each time you start and BEFORE you push the mode button). And for the vast majority of RV's performance mode IS the pre-select.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #9 – March 15, 2020, 10:48:11 am

Before reading anything I thought the economy mode reduced overall available HP therefore reducing fuel consumption. In order to maintain the desired speed the transmission would shift earlier since the available power was reduced.

So I would have expected the extra shifting mode (shifting earlier and every time I pressed on the accelerator) to be the economy mode. I thought I proved this to myself while doing a road test and timing the zero to 70 acceleration. I guess I will have to verify it next tine I am out on the road.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #10 – March 15, 2020, 10:52:09 am

Quote from: Eric & Alena + 3 – March 15, 2020, 10:48:11 am

So I would have expected the extra shifting mode (shifting earlier and every time I pressed on the accelerator) to be the economy mode. I thought I proved this to myself while doing a road test and timing the zero to 70 acceleration.

NO, exact opposite. In economy mode the engine operates at a LOWER RPM. Upshifts earlier/at lower RPM), downshifts later.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #11 – March 15, 2020, 11:10:25 am

A lot of us just leave the transmission in Mode all the time. Once you get used to how your rig performs you can anticipate the right time to downshift on a climb and do it manually. More fun that way too.
jor

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #12 – March 15, 2020, 11:15:53 am

That is exactly what I do-- leave it in economy mode 99% of the time and use the down/up arrows as desired. As a driver, you can be PROactive. But, a transmission can only be REactive-- acting on what happened well behind you. The heavier the rig the more momentum so it is reacting to what happened even further behind you.

The only time I use power/performance mode is where I am concentrating on driving and don't want an extra thing on my mind and don't mind throwing more fuel for a small performance gain-- like when passing on two lane roads.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #13 – March 15, 2020, 11:32:50 am

Bret

I believe I am trying to say the same thing you said. The coach definitely Shifts way more often when I press my economy button (off by default). I have never payed attention to the RPM when shifting under load in either mode.

I will have to experiment and pay attention to the differences. I do distinctly remember a considerable difference in getting on the freeway ramp between the two modes.

Always something to learn with these rigs!

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #14 – March 15, 2020, 11:40:14 am

Quote from: Eric & Alena + 3 – March 15, 2020, 11:32:50 am

Brett

The coach definitely Shifts way more often when I press my economy button (off by default). I have never payed attention to the RPM when shifting under load in either mode.

Shifting "way more often" is power/performance mode. In economy mode there will quite a less down/up/down shifting.

Again, this will only occur in rolling hills. On flat ground on cruise, you will be in 6th gear in either mode. It is only at close to WOT that any downshifting difference will occur.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #15 – March 15, 2020, 01:42:23 pm

Then it does sound like I am backwards. It also appeared my "mode" and light are backwards. I am really surprised if I have always been in economy mode since I have never felt under powered even fully loaded towing a 5000lbs van. Crazy awesome!

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #16 – March 15, 2020, 01:49:46 pm

Eric,

Do the acceleration test I outlined above and tell us what you find.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #17 – March 15, 2020, 03:36:25 pm

On my allison pad it says Power next to the mode light. So when it is lit I know I am in the power mode. Is anyone else's like that ?

Mark

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #18 – March 16, 2020, 03:20:51 am

Part of the "feel" is the engines torque output.

My coach downshifted a lot under medium throttle. Horsepower vs torque.

That got me to look for parasitic loss reductions to increase the engines torque.

I went through almost everything possible without hot rodding the engines programming.

I build off road racing motorcycle engines and built and/or sold hundreds of coaches personally.

Reducing ALL the losses made my coach drive in performance mode like it did before in economy mode.

Now it stays in gear under fairly heavy throttle inputs vs downshift.

Did not like the way it ran before. Revvy. Now much more torquey.

I prefer these fixes vs paint and interior mods. Those to come later if at all.

Works better in economy mode also.

Still underpowered vs a lot of similar displacement diesels I have driven before in the biz.

My speeds up grades does match a lot of other owners I have had contact with so i think it's normal

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #19 – March 16, 2020, 09:33:39 am

Quote from: MAZ date=1584235879 link=msg=383313]
Mine is the same. It defaults to Economy on startup and goes into power mode when I select it.

Mark
[/quote]
[quote author=MAZ – March 15, 2020, 03:36:25 pm

g=383412 date=1584300985]
On my allison pad it says Power next to the mode light. So when it is lit I know I am in the power mode. Is anyone else's like that ?

Mark

I just looked at my Allison pad, it says POWER above the MODE button. Hmmmmm, Gotta love this forum. Anyone call the mothership yet?

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #20 – March 16, 2020, 09:37:29 am

Guys,

Just do the 0 to 50 mph or so test, noting highest RPM before upshift.

That will tell you exactly which is power/performance and which is economy mode.

Even if the factory could look it up for you, that would assume you still have the original Allison ECU and that it has never been reprogrammed.

Re: ALLISON TRANSMISSION MODE BUTTON

Reply #21 – March 16, 2020, 12:14:12 pm

Exactly the way ours works. Economy by default, power when the mode is on and it is labeled that way on control panel. I usually turn on the mode and control the downshift with the throttle or with the control pad. Our MPG varies between 9.3 to just over 10. Lifetime on the ECM on the report taken by Cummins before we got the coach showed 9.63 MPG. Only once so far when calculating MPG after a lot of mountain driving, did I get a figure under 9 MPG and that was around 8.8 MPG.
Don

Quote from: MAZ – March 15, 2020, 03:36:25 pm

On my allison pad it says Power next to the mode light. So when it is lit I know I am in the power mode. Is anyone else's like that ?

Mark

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