Manual Shifting Allison

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Manual Shifting Allison

April 27, 2017, 03:25:07 pm

I hesitate asking such a simple question, it just runs up my post count with no contribution to the technicalities or gee whiz of FT ownership. But this is important to me.....!

Do you frequently shift gears manually? We talk about changing the rpm to help with cooling or braking, easing up on the Retarder.

I know that if I shift on the fly and it does not want to, it will not (thankfully!). So it seems ok.....but the other option is to stop and shift and set the top gear at some level.

Is that what you all are doing... manually shifting frequently to hit the cooling and braking optimum points rather than awaiting automatic shifts? What I have been doing is shifting on the fly.....is that what all do, it is okay?

example, a mountain pass grade, I need to drop into 3 or 4 on way up or down. As I am moving, and tach looks a good range to do so, I push an up or down arrow. As it can, the rpm changes as does the gear. In this I am having to trust the governor whatever will not let it make a move that over-revs the engine even if i asked for a gear that would be wrong at that speed......my interpretation

And in another question, I read in some thread to not shift out of D into N at a red light. I forget the reason but seemed logical so I quit doing that though I did like to shift to N at a long light. I think the concern was it may wear out the shift pad? (bet I got that wrong!) But even more, and really scary, it avoids accidentally shifting into R as leave the light (oh my!).

And while I have your attention, I do not turn off the engine when taking on diesel.

Re: Manual Shifting Allison

Reply #1 – April 27, 2017, 03:29:47 pm

I let ours do all the downshifting on the upside of a grade, but sometimes will lock a lower gear going down to aid the retarder.

Re: Manual Shifting Allison

Reply #2 – April 27, 2017, 03:49:19 pm

I will sometimes help it by downshifting going UP if it sounds like it is laboring and often downshift coming down the mountains to ease the load on the retarder and to keep the temperatures down.
I learned the hard way when I first got this one and ran down a L O N G mountain in 6th with the retarder all the way!! By the time I reached the bottom it was giving the chime, and then shut down before it got too hot!!!!!!!!!!!!!!!! Then no power steering etc. but I was almost on the level and got it stopped. A quick call to FT enlightened me to whichever gear it needs to go UP the hill is the one to use coming DOWN!!
Speedbird 1.

Re: Manual Shifting Allison

Reply #3 – April 27, 2017, 04:04:31 pm

Dear Craneman

For whatever reason, when we first got ours and tried a particular pass, it was very slow to downshift on the way up. Seemed climbing on 1100 rpm. Then a hard shift. I was new to this, not familiar with what it going to do or needed from me.

Then, after that, a friend told me to be sure to shift into third before began the climb, that otherwise the coach would be slow to shift to where it needed to be . So now I shift before get very far into the climb

This is not a very high altitude climb by mountain standards but it is steep going up, and down, for its 1000 ft to top at about 9800 ft

thanks

Re: Manual Shifting Allison

Reply #4 – April 27, 2017, 04:19:19 pm

Mike,
I only have driven up the Bishop grade for my information. we do this twice a year with me pulling '01 Grand Cherokee. This June I will be pulling the boat and my brother will tow his Tahoe. The boat is 2000 lbs. lighter but maybe the downshifting might match what you have. I watch the tach. and it seems to shift before lugging down. I drive a '81 International that weighs 32,000 lbs. and has a 210 HP 605 lbs. torque @ 1400 rpm. motor with a RT13 trans. Possibly the motorhome has me fooled as I am not used to the torque of it.

Re: Manual Shifting Allison

Reply #5 – April 27, 2017, 04:22:30 pm

Quote from: Michael & Jackie – April 27, 2017, 03:25:07 pm

And while I have your attention, I do not turn off the engine when taking on diesel.

I no longer turn my engine off when refueling thirty plus hours stuck on a fuel isle will do that to you and I do not turn off the engine when dumping the tanks either for the same reason.

Roland

Re: Manual Shifting Allison

Reply #6 – April 27, 2017, 04:24:40 pm

Mike here in the West and all mountains we drive up and down.i always watch my RPMs.with my Detroit it may differ then your Cummins and only having a 4 speed I manually down shift all the time. Driving by my temp gauge.. and as you know what ever gear you go up a steep grade that is the gear you can safely go down. You can go down a hill fast and burn up you brakes or tranny with a retarded or go down slow and never have a problem. Anyway that's what I do good luck.

Re: Manual Shifting Allison

Reply #7 – April 27, 2017, 04:32:18 pm

As to manually shifting going uphill I do that always when I know I am going up a long grade. I shift before the rpm's get low enough to kick in the next gear I like to keep my rpm's up when climbing. Once you lose the rpm's you never get them back. I don't know about anyone else's tranny but mine will go real low on rpm's before it shifts so I take control after all I know I'm climbing a hill the tranny does not.

Roland

Re: Manual Shifting Allison

Reply #8 – April 27, 2017, 04:38:25 pm

I set my maximum gear up or down and let the tranny do the rest.
If fourth or fifth is all it can pull going up, I will limit it to that gear, that stops the up shift if you have to lift for a few seconds.

I see what gear the coach is happy with going up and then limit the tranny to the same gear going down.
Fourth gear up = fourth gear down.

I also use the retarder going down any steep hill.

I am always towing a 10,000lb trailer as well.

Steve

Re: Manual Shifting Allison

Reply #9 – April 27, 2017, 05:04:55 pm

Yes, I treat the Allison 3000/4000 like a manual transmission. I "overrule" the automatic, particularly in the mountains. Why? Because, I can be PROactive. The transmission is only REactive-- because of momentum, only seeing what happened well behind you. It has no idea that you only have 100' left to the top of the grade, or about to tackle (i.e. in front of you) an 8% grade.

As Mike observed, the Allison is what I call "idiot-proof". If you select a gear that would endanger the engine, the Allison ECM "translates" your request into "I will do what you ask as soon as I can SAFELY do so. Basically, you are selecting what Allison refers to as a "pre-select" gear. So, you could down arrow to 2 at 60 MPH and it will downshift a gear at a time until it reaches 2nd gear. It will NOT overspeed the engine.

So, feel comfortable leaving it D if you like. But, also feel comfortable being proactive with the up/down arrows and/or the mode button.

Re: Manual Shifting Allison

Reply #10 – April 27, 2017, 05:15:25 pm

Thanks to each of you.....I feel more secure in my driving with shifting

I know Mr. Wolfe has reported on such before, and I think others of you have made educational comments before.

My filing system is not so good as Roger whom I think has it all electronic. I have a three ring with tabs, such as Allison. I need to make a copy of these and put in that tab.

Now if I can just find the three ring next time I get to thinking on this.....

Thanks again, and I bet some readers will like the refresher on these couple of topics....shifting and cooling and fueling

Re: Manual Shifting Allison

Reply #11 – April 27, 2017, 05:29:06 pm

Never hesitate to ask. Look what came out of this one!!

In my case I knew nothing about the fact that too much use of the retarder would cause the engine to shut down and FT said nothing about it when I bought it from them.

Always easier to ask than to find out the hard way and no question is a silly one!!
Speedbird 1.

Re: Manual Shifting Allison

Reply #12 – April 27, 2017, 06:08:43 pm

Great refresher, all. I never knew or had forgotten that no matter

where you selected for the Allison it would not go directly there

but would stair step down, thus not going to sling itself apart.

Thanks,

Carter-

Re: Manual Shifting Allison

Reply #13 – April 27, 2017, 07:51:35 pm

On my previous coach, Cummins 8.3 and Allison 3060, I manually downshifted on climbs to keep it cooler and because the coach shifted late on it's own.

On our new to us 2003 U320, I find the auto shift points for climbs satisfactory except for one case today. On a hard mountain climb in Montana today the right lane was closed, and all traffic was in the left lane. Heavy semi trucks were bogged down, and the coach wanted to stay in 4th at what I felt too low of an rpm, so I manually downshifted into 3rd.

I always manually downshift on the downgrades. One advantage to manually downshifting on the climb is that you will already be in a gear correct or close to correct for the downgrade.

Re: Manual Shifting Allison

Reply #14 – April 27, 2017, 08:08:54 pm

Shift anytime you want going up or down. Drive by tach, not spedo. Don't shift under hard throttle, but it probably won't change gears anyways. Tranny almost ALWAYS protects itself, it is very smart. Don't let tranny 'hunt' between two gears back and forth, shift down to stop it. Can't hurt this baby. Never shift to neutral, that is unless you want to sit at that spot for the rest of the day. Never turn engine off at fuel up (for the same reason). Often better to manually downshift before the computer makes the decision to down shift. Always downshift and go slower up hills to prevent overheating. Get used to driving slow and letting others pass when necessary. Get a pyrometer and also drive by exhaust gas temp, along with tachometer, no better way to protect engine and components and get to the top safely.

Re: Manual Shifting Allison

Reply #15 – April 27, 2017, 08:34:25 pm

Another great reason to run the Silverleaf software as it will show you your retarder temperature. Use too much retarder and watch the temp quickly head towards 300 degrees while the analog dash gauge barely starts to move up from around 170 degrees. Really gets your attention going down a 6% grade while grossing out at around 50K#!

Gearing down and a little judicious use of the brakes and retarder seems to be the best way to go for me.

Steve

Re: Manual Shifting Allison

Reply #16 – April 27, 2017, 09:04:34 pm

Quote from: Barry & Cindy – April 27, 2017, 08:08:54 pm

. Never shift to neutral, that is unless you want to sit at that spot for the rest of the day. Never turn engine off at fuel up (for the same reason).

Don't see any reason not to turn off the engine at a fuel stop. I wouldn't drive the coach if I didn't think it was going to start (and instantly) every time I shut it off. If your engine ever hesitates or fails to start, it's time to find the problem so you don't worry every time the key is turned off. The only time to idle it is if it's been pulling hard and you want to bring down the oil temperature so you don't get any coking in the turbo.

I turn off our cars when fueling and do the same with the coach.

Pierce

Re: Manual Shifting Allison

Reply #17 – April 27, 2017, 09:24:53 pm

I manually shift when going up or down big hills, I like to keep RPMs up 17-1800 seems to keep things happy. I will also set the max top gear when Im in lower speed zones no need trying to run 6th gear at 55.

I also don't turn the engine off at dumps and fuel stops, only where it's going to be parked out of everyone's way.

Re: Manual Shifting Allison

Reply #18 – April 27, 2017, 09:36:38 pm

Not for motorhomes yet, but can see it coming. https://www.arb.ca.gov/msprog/truck-idling/factsheet.pdf

Re: Manual Shifting Allison

Reply #19 – April 27, 2017, 09:44:01 pm

I live like wolfe10 does. Turn off the "mode" and shift it as needed.

Or wanted. Slightly faster up grade. Why not? Half the fun to outwit the Mechanical simple brain.

As far as the idling standard we are neither a truck or bus.

Yosemite no gen Rv campground is full of high idling Mercedes diesel class "b" vans generating 110.

Thought "where's the noise from?"

Re: Manual Shifting Allison

Reply #20 – April 27, 2017, 10:17:37 pm

Quote from: Caflashbob – April 27, 2017, 09:44:01 pm

I live like wolfe10 does. Turn off the "mode" and shift it as needed.

Perhaps I misunderstand or we are just saying the same thing differently. I drive in economy mode 99% of the time and then I, repeat I decide if I need to downshift. So, each time I start the engine, I hit the mode button to select economy mode.

Said another way, my "default" when driving is to have the Allison drive for economy (upshifting when it can grab the next gear at peak torque RPM rather than winding up to peak HP RPM before shifting). If I want more performance, I use the down arrow. The only time I drive in power mode is in situations like passing on two lane roads where I am willing to pay for extra fuel for a little better performance.

BTW, any Allison dealer can reprogram the ECM so that economy mode is the standard and you would have to push the mode button to get to performance mode. I'm too cheap to spend the money to have it reprogrammed. Easy enough to just push the button.

Re: Manual Shifting Allison

Reply #21 – April 27, 2017, 10:33:57 pm

Some are type b and some are type a drivers.

My foolproof test selling new Foretravels was to diagram a two lane on each side interesection.

I showed a car in the curb lane and the inside lane open.

Then I asked the customer if they were coming up behind the curb lane car would they pull up behind the car or move over and take the inside open lane?

Lots of laughs and interspection.

If you move to the empty lane turn off the mode and see what's faster up the hills. Shortshifting torque or downshifting hp.

Only testing will show.

And whether it's important to you?

Where would you be in my diagram, behind the car or move over to the open lane in a car.

You are really bad if you would pull over in your coach towing...

Re: Manual Shifting Allison

Reply #22 – April 28, 2017, 08:41:34 am

Quote from: wolfe10 – April 27, 2017, 05:04:55 pm

Yes, I treat the Allison 3000/4000 like a manual transmission. I "overrule" the automatic, particularly in the mountains. Why? Because, I can be PROactive. The transmission is only REactive-- because of momentum, only seeing what happened well behind you. It has no idea that you only have 100' left to the top of the grade, or about to tackle (i.e. in front of you) an 8% grade.

As Mike observed, the Allison is what I call "idiot-proof". If you select a gear that would endanger the engine, the Allison ECM "translates" your request into "I will do what you ask as soon as I can SAFELY do so. Basically, you are selecting what Allison refers to as a "pre-select" gear. So, you could down arrow to 2 at 60 MPH and it will downshift a gear at a time until it reaches 2nd gear. It will NOT overspeed the engine.

So, feel comfortable leaving it D if you like. But, also feel comfortable being proactive with the up/down arrows and/or the mode button.

But what happens when you are in ,say, 3rd and the momentum (and gravity) increases the rpms toward the danger point?
(As I understand it,something like 2,700 should be the max for the 8.3)
The Allison is not going to UPSHIFT is it?

Re: Manual Shifting Allison

Reply #23 – April 28, 2017, 09:31:47 am

Quote from: TheBrays – April 28, 2017, 08:41:34 am

But what happens when you are in ,say, 3rd and the momentum (and gravity) increases the rpms toward the danger point?
(As I understand it,something like 2,700 should be the max for the 8.3)
The Allison is not going to UPSHIFT is it?

YES, it will upshift! It's primary job is to protect the engine.

So, if you find your speed creeping up toward where that would occur, step on the brakes firmly and long enough to allow you to drop to the next lower gear (that down arrow).

Re: Manual Shifting Allison

Reply #24 – April 28, 2017, 05:03:10 pm

In the mountains getting coolant flow increase with a selection of a lower gear on the uphill will aid in keeping temps reasonable. Coming down intermittent app of retard will run tranny temp up but if already in a lower gear will also expedite tranny temp reduction. I miss my coach

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