Allison reprogram review in Seneca

[Mark S]

Originally Posted by Crossingover

Not as convenient as a reflash of the Allison's TCM to performance mode, but why not move the shift selector to the '3' or '2' position to force and hold a downshift? That way you could have performance when needed, and economy at other times.

I tried the shifting to 3rd. The RPMs were too high to maintain a reasonable climbing speed. Now if I was able to shift to 4 th, that might be a different story. But alas, that was not an option.

And there was absolutely no change in my mpg economy. I got just under 10 mpg at 65 mph towing the Jeep.

[Dustdevil]

Originally Posted by Crossingover

Not as convenient as a reflash of the Allison's TCM to performance mode, but why not move the shift selector to the '3' or '2' position to force and hold a downshift? That way you could have performance when needed, and economy at other times.

Originally Posted by Mark S

I tried the shifting to 3rd. The RPMs were too high to maintain a reasonable climbing speed. Now if I was able to shift to 4 th, that might be a different story. But alas, that was not an option.

And there was absolutely no change in my mpg economy. I got just under 10 mpg at 65 mph towing the Jeep.

The way I understand it, the problem with doing this with the latest versions of the Allison is that it is essentially a 6 speed, with the top two gears being overdrive ratios. What that means is that if you are shifting out of OD, you are going down TWO gears, not simply one. And the same if you are using the PRNDL shifter to drop down out of D. So, either your speed must decrease significantly to handle the much lower 3rd gear, or you must scream the engine well past the point of reason to keep it in that gear. This reprogram allows the transmission to drop down one gear out of 6th or 5th, possibly remain in 5th or 4th, and remain there long enough and under enough throttle load that it won't keep trying to bump up to a gear that is too high to pull the hill. So, it will tend to remain in the highest gear in which it's capable of climbing the hill, as long as you don't let up on the throttle significantly.

We didn't have this issue with the 5 speed Allison, because locking out OD only drops down one gear to 4th, and the next gear down (3rd) is selectable on the PRNDL shifter. So, we can hold the older trans in 3rd, 4th, or 5th. On these new 6 speeds, it sounds like the primary program is MPG-priority, rather than performance priority, which is what the tow/haul button used to do on the Duramax/Allison pickup trucks. It switched from Economy mode to Performance mode and allowed selection by the driver of that shift schedule that prioritized performance.

[RVermont]

Three letters. WOW.

Just got the Seneca reprogrammed to be in performance mode and it is significantly better. I can actually accelerate up hills. You put your foot down at 55 and it drops gears and starts to move out. The tech explained that we have a 2600 rpm engine and the economy mode is 2300 rpm max. So about 10-15% more power and speed.

I asked why he thought these were like that and he felt it was due to requirements on freight liner to improve fuel economy. He explained that most trucks are coming out with economy and they are flashing a lot of units. The 3000mh in the newest models has the button controls and it should be selectable on that unit.

Bottom line if you don't have the OD cancel button this is a worthwhile investment. I could not get the shop to do this under Warrantee so I will send it on to Allison directly and see what I can get it out of them. Even if I can't the two hours of labor cost is well worth the price.


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[Mark S]

I am glad you are happy with the change. I now feel I have adequate power and I even passed people on the Florida turnpike yesterday. Big difference.

And I don't think it affects the fuel economy.

[RyRoRyan]

"3ALACXFC0JDJG1060 currently has the performance shift schedule on secondary, which is controlled by wire 142. If the OEM has not provided any means of controlling this wire, then you will always be in economy mode."


So let me ask this...it sounds like the performance shift schedule is built in...granted not fully setup like Mark has with the upper end shift as well, but at least something. I am thinking that if we just found a way to "control" wire 142, by whatever that may mean, then those of us who dont live near an allison dealership can prob add a switch in ourselves and get the performance schedule with the flick of a switch.

On a side note, now that the 2018's have a 3000 series trans, they get the electric gear selector which has the mode button built right in. That means they have eco and performance mode built right in.

[jschulz1720]

Originally Posted by RyRoRyan

"3ALACXFC0JDJG1060 currently has the performance shift schedule on secondary, which is controlled by wire 142. If the OEM has not provided any means of controlling this wire, then you will always be in economy mode."


So let me ask this...it sounds like the performance shift schedule is built in...granted not fully setup like Mark has with the upper end shift as well, but at least something. I am thinking that if we just found a way to "control" wire 142, by whatever that may mean, then those of us who dont live near an allison dealership can prob add a switch in ourselves and get the performance schedule with the flick of a switch.

On a side note, now that the 2018's have a 3000 series trans, they get the electric gear selector which has the mode button built right in. That means they have eco and performance mode built right in.

I agree. I would like to know the difference between the 142 wire and the 161 wire.

[RyRoRyan]

The 142 wire is for the performance shift schedule. This wire is not hooked up on ANY of the Jayco M2's as far as I know. This tells the trans to up and downshift at different points in ALL gears. In the GMC trucks this would effectively be the Tow/Haul mode switch

The 161 wire is for the OD lockout or OD off. This switch DOES exist on my 2016 and I know goes back to at least 2014 and maybe even older. It does NOT exist on 2017 units. This switch will limit the transmission to gears 1-4 as 5 and 6 are overdrive gears. I cannot confirm this but other members have stated that this switch also slightly changes the shifting, however I dont believe it does. I think it only effectively limits the gear selection to 4 gears. I basically pretend that that switch is the notch that missing between the D and the 3 on my shifter.

If I had it my way, I would have them rather put in the tow/haul (performance) switch than the OD off switch. Hopefully someone with some real knowledge of their rig and where the TCM is and where exactly 142 is and how to signal it (+5v, +12v, close a loop, etc) might be able to figure it out and shed some light to the rest of us here.

[ready2retire&drive]

I am glad it worked , I think that this upgrade will not only make these units safer as they can now go with the flow, but may also improve the fuel economy a little. Three of us have had noticeable great results , there may be a flurry of reprograms and satisfied smiles ahead for a lot of Seneca owners out there.

[jschulz1720]

I would think having both switches would be nice.

[RVermont]

I briefly discussed this with the Allison tech and he felt that running in performance mode would provide the needed benefits and the added expense of installing a switch would probably not be worth the efforts. He did say that it is crazy that these units don't have air dryers especially in the north were a frozen air line means you don't stop.



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[RyRoRyan]

Quick question. I know for Mark he got it done under warranty. Has anyone else done this. Will Allison actually cover this reprogram under warranty? If not, what have been your average prices you paid to have this done?

[javamon]

Originally Posted by RyRoRyan

Quick question. I know for Mark he got it done under warranty. Has anyone else done this. Will Allison actually cover this reprogram under warranty? If not, what have been your average prices you paid to have this done?

I was surprised that Mark was able to get this done under warranty. IMO, this is not a defect and definitely not Allison's fault. Just a huge oversight by JAYCO. RVermont was charged 2 hours of labor for this, so I'm guessing he paid somewhere in the $200 range. Two hours seems excessive for a reprogram, but some shops have a minimum hour policy.

[RVermont]

The service writer would not even discuss submitting this as a warrantee item. The two hours are over kill during his time I spent 15-20 minutes with the tech going over the unit and then had them check alignment of the headlights. These were still 4 inches low even after I raised them 12 inches when I got the unit.

The reprogram process is simple but requires several steps.

The tech has to hook and down load current programming. Then they have to write an email to Allison for the new program. Then depending on how quickly Allison gets back to them they receive the program and then install it in the transmission. So I would estimate a normal time of 1-1.5 hours. $100-150.




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[RyRoRyan]

So I called Stewart and Stevenson of Albuquerque to have them perform this reprogram for me. Even though I never gave him a VIN or anything other than that it was a M2 with a 2500 Allison in it, the guy was adamant that I did not need a reprogram (to make primary) or a switch to access the secondary shift schedule as just my putting my pedal to the floor that the trans would know that I wanted full power and automatically change to the performance mode. I fully believe this to be BS. He didnt want to make an appointment or anything because he felt as if he could do nothing. Now this totally sucks because the next closest dealer who can actually reprogram right now is about 200 miles away. (Bruckners truck service is listed as a reprogrammer on Allisons website, but when I called, they said the only tech who knew how to do it left the company so they cant do it right now.)

I have since emailed Matt at Allison and asked to see if he can investigate the dealers claims and educate either myself or the dealer in the correct operation of the unit.

Ill post an update when I hear back from Matt.

[RyRoRyan]

Update....Matt investigated and the dealer thought my trans had the Dynamic Shift Sensing feature, which it does not. Matt then worked with the dealer and already sent him the calibration file. I will be there on Friday morning to get it done.

[Mark S]

That's great news. Anxious to hear your impression.

Matt is an awesome resource. I wonder if we all need to tell Matt's boss how good he is at assisting owners.

[RVermont]

This site really provides valuable information. Without this site we all would be sitting there accepting information from dealers and others that are not invested in us. I am getting the new sway bar based on information for others. The freightliner dealer was just going to replace the rubber mounts until i told them about the service bulletin.

Thanks to all who provide this information for the benefits of all.


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[Dananu]

I hadn't paid much attention to shift rpms as I was happy with performance. Mine is a 2013 chassis. I never use the OD off switch as all seems well as is. I usually have cgvw around 32,000. Today coming from the oregon coast to Bend, sea level to over 4,000 ft I watched rpms. Full throttle would downshift at 1,700 and would hold until 2,500 before upshift. Maybe mine is set to performance already?

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[Crossingover]

Reflash 101: Where is the TCM S/N located?

[javamon]

Originally Posted by Crossingover

Reflash 101: Where is the TCM S/N located?

I believe you mean the transmission S/N. It's on a metal plate, right rear of transmission. It's hard to see unless you are on a lift. I just crawled underneath, took my phone, held it up close to the plate and took several pictures.