Downshifting manually?

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4ducksrus

4ducksrus

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Nov 17, 2010
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My DH does all the driving (for now) until I feel comfortable driving our new rig.  This is our first DP and we are trying to work out the kinks.  On our last weekend trip my DH said that he couldn't figure out how to manually downshift.  When we got home he started going through all of our manuals to try and find out where it says how to do it.  He says he can't find where it shows the same "codes" he is getting in the readout.  When driving our read out doesn't just say D, D1, D2, etc.  it says, G?, 44, things like that.  I'm sure someone out there will understand this because like I said, I'm not driving it so I'm not clear on what he's asking me to ask!  I guess bottom line, he just wants to know how to downshift manually?  Thanks
 
I assume you have the push button Allison 3000 transmission?

If so, the touch pad used to select the gear has an up and down arrow which tells the transmission what you want the  "highest" gear available to be.  In other words, if you're headed down a hill and push the down arrow, the left digit should change from 6 to 5 if you push the button once.  It will continue to select lower gears each time you push it.  This does not mean that your transmission will shift down at that time however.  The computer tells the transmission when it's ok to down shift without over reving the engine.  The two digits you mentioned in the read out, "44" should display the highest gear requested on the left and the gear actually engaged on the right.

Something which could be causing confusion is the engine brake.  If he drives with it engaged, it will automatically request a down shift to 2nd gear and engage the engine brake.  You won't be able to "down shift" manually with the engine brake engaged.  I suspect this might be the problem he's seeing.  It's possible for the computer to be programmed to act differently than described above but I believe this is the way most come from the factory.

Good Luck...

Rick
 
4ducksrus said:
When driving our read out doesn't just say D, D1, D2, etc.  it says, G?, 44, things like that. 
Click to expand...

If you have an allison transmission, as Orick mentions, you will not have D, D1, D2, etc.  You will have 6,5,4,3,2,1.  I'm betting what you are seeing as a "G" is really that the transmission is in 5.  Your selector on the left hand side of the driver's seat should say  "D" , "R". and "N".  When you select "D" you will automatically go to 6th gear.  Then you can use the "down" arrow which is really an arrow to go to the next lower gear etc, with each click.  There is also an "up" arrow for going up through the gears.

Also, Orick has a good idea, you could have the engine brake on; and it will stay in 2nd gear as long as your foot is off of the gas pedal.  If you push on the gas pedal, the engine brake will disengage and you will then be in what ever gear you have chosen.  If you choose "D" it will be automatic, if you use the down arrow you will go into 5th, then 4th etc.  To get out of the manual, you need to hit "D" again.

Hope this  helps!

BTW, learn to drive that thing...It's fun.  My husband and I fuss over who is going to drive.  ::)

Marsha~
 
In driving through one state with very very long slopes. I found that even with the engine brake switch ON the allison transmission will upshift when the engine speed gets high enough.. Then you have to use brakes to slow it back down (it will quickly downshift as the rig slows) and cycle it over again.

IF it stayed in 2nd to the bottom of the hill... Pistons would be a-popping, and since I'm sitting on them, I'd rather they not do that (i'm in the line of fire)
 
We are also talking about the "mode" on our transmission.  Our manual says that we can set it to another mode and that's where some of the confusion is coming from.  Do any of you use this option?
 
Hi Mikie,

You know how much I love to give you links to manuals ;) . I presume you recieved this one with your coach but you said DH couldn't find the answers so I can't resist in case you don't have it. http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=OM3349EN.pdf

Page 21&22 of the manual talks about shifting and what the code means. I only breezed through it but there is a ton of useful info in that thing so DH might want to read it through, it's only 128 pages LOL. Just breezing through I ran accross all kind of interesting tidbits, good stuff!

Have a great day!
Dar
 
The reference to "engine brake" our unit has a switch for an "exhaust brake" are we talking the same thing?  This is very confusing....LOL
 
We also have the "Mode" button.  If I push it, the engine goes into "economy".  That's the only mode that I know about.  If you push the "mode" button, a little red light will come on so that you know you are in "economy".  If you decide to use this, be sure and shut it off when going up a hill.  The "economy" mode changes the shifting points. 

We really haven't found much difference in fuel economy with the "economy" mode button engaged.

This should all be stuff in the manuals you got from the dealer. 

Marsha~
 
4ducksrus said:
The reference to "engine brake" our unit has a switch for an "exhaust brake" are we talking the same thing?  This is very confusing....LOL
Click to expand...

Basically, "Yes".  Different types, but have the same effect to some extent.  There is an article in the library that explains them.

Marsha~
 
Economy mode on the Allison transmission lowers the shift points (by 200 rpm, I believe) so it doesn't "hunt" while driving in rolling terrain.  This is the purpose in an RV application.  The Mode button can be programmed to have a different effect in other applications, but this is the most useful for an RV.
 
Thank you so much for all of your replies.  In the FL manual under transmissions, it talks about a primary shift mode (normal) and a secondary shift mode that can be programmed.  Has anyone experimented with the secondary shift mode?
 
The secondary shift mode is what we have been referring to as Economy mode.  As I said above, the mode switch can be programmed to do different things, but the Economy mode is the most useful for RVs.  The programming is not something you can do, it has to be done by an Allison shop using a computer.
 
During a talk by an Allison guy in Coburg, he said that Marathon requests that the transmissions for their coaches be programmed to economy mode. But he also said that he gets lots of requests from owners to re-program their transmissions to normal/standard mode.
 
The basic design of the Allison transmission is to have the "economy" mode as the standard. The extra oomph the non-economy mode gives prospective buyers had the industry standardize on the economy mode as not being the default for marketing purposes. Based on the recommendation by a Cummins presenter at a Cummins seminar, I drove from Minot, ND to Seattle, WA with the tranny always in economy mode, including thru the Rockies. My engine has enough hp and torque to manage that, tho I didn't win any gold medals for being the first up the mountains ::)
 
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