Allison 2000/3000 Unlocking 6th gear?

[Blkjacksabbath]

Originally Posted by Elliot Naess

I may have found it.

Try this for the...

1000 - 2000 series:

1000-2000 Series

3000 series:

3000 Series

On each of those pages, scroll down a little and you will see three red buttons for the model numbers. Each button opens a PDF.

If you want the 4000 series and the rest of them, hover the mouse on "TRANSMISSIONS" in red near the top of the page. You get a window with all the models series on the right.

Guys; If this works for you, and seems useful, I can start a new thread and ask that it become a Sticky like the AT 545 and MT 643 info.

Are you a wizard??

[Elliot Naess]

If the hat is anything to go by....

[jhagan]

Hello. I have a handful of buses that my company purchased that came with the 5-speed MD 3060, paired to the CAT 3126b and DT 466. We recieved the liability release waiver from both OEMs (Thomas and IC) and our local Allison dealer simply hooked up to the TCM and unlocked the 6th gear as well as uploaded the Economy Mode which lowers the shift points when activated (red light comes on when Mode button is pushed). On average, the 6th OD kicks in around 49 MPH and reduces the RPMs by 300-350. It only costs us $80 each visit to the dealer. Both OEMs encouraged the drive shafts to be heavier duty, however, we haven't experienced any issues. I highly encourage anyone using their 3000s to unlock 6th. Well worth the investment.

[EastCoastCB]

Originally Posted by Elliot Naess

If the hat is anything to go by....

You remind me of this guy

[boojiewoojie]

jhagen, can't get your thumbnail to open; don't know if it's relevant to your post....

So, what steps did you go through to get a liability release waiver, specifically IH? Did you just call them with a VIN number and ask for a waiver? Was there anyone specifically you contacted? I'm about to take my bus out of service in May and would love to get a jump on it.

The Symrna, TN Allison shop said all they needed was the waiver....

[AlleyCat67]

And I need the process for Thomas, if you please.....

[jhagan]

The first step is to contact your International bus dealership and speak with the Service department..probably the manager. Let them know you need them to place a service order with International to recieve a letter on OEM letter head to verify the bus is equipped with the MD3060 and is OKAY to unlock the 6th gear. The letter will have certain requirements that the Allison dealer mayou or may not check such as minimum rear end ratios, 75 MPH tires, and an acceptable drive shaft. I received my letter from International within a week. You, then, send it to your local Allison dealer. They will forward it to Allison Headquarters, and then send you a liability release. Once you sign, they release the programming to your local dealer. Takes a few minutes.

[jhagan]

See me response below. Thomas is known to not approve of the rear end ratios aren't acceptable.

[lucasd]

Given that the 3000 series seems to be pretty well documented in publicly available service manuals and such, has anyone just given up on getting official permission and wired a manual bypass in between the ECU and the transmission solenoids?

I've seen some documentation that even goes so far as to discuss what hz the PWM signal from the controller to the solenoids runs at.

Granted, I don't know much about transmissions, so maybe this is more complicated than it seems. Does the ECU just flip one set of solenoids off and turn the others on, or is there a ramp-down/ramp-up process during which the PWM signal to the solenoids for the current gear is adjusted down while the duty cycle of the PWM signal for the upcoming gear is phased up to a 100% duty cycle? If so, is it the same all the time, or does the switchover timing vary depending on speed/current gear/moon phase/etc?

By "manual" control I don't mean a literal switch, of course. Since it involves a PWM system, I'm assuming it's not just an on-off arrangement, so the custom control would have to make use of a microcontroller that could properly implement the duty cycle phase-in/phase-out portion of the shift sequence. If the timing of this sequence is fairly reliable, however, then it seems like it could be duplicated easily enough. The factory control could either be supplied with dummy inputs to convince it that the bus is actually in 5th gear while the custom module moves it in and out of 6th, or it could be replaced completely, depending on preference.

[PNW_Steve]

Originally Posted by lucasd

Given that the 3000 series seems to be pretty well documented in publicly available service manuals and such, has anyone just given up on getting official permission and wired a manual bypass in between the ECU and the transmission solenoids?

I've seen some documentation that even goes so far as to discuss what hz the PWM signal from the controller to the solenoids runs at.

Granted, I don't know much about transmissions, so maybe this is more complicated than it seems. Does the ECU just flip one set of solenoids off and turn the others on, or is there a ramp-down/ramp-up process during which the PWM signal to the solenoids for the current gear is adjusted down while the duty cycle of the PWM signal for the upcoming gear is phased up to a 100% duty cycle? If so, is it the same all the time, or does the switchover timing vary depending on speed/current gear/moon phase/etc?

By "manual" control I don't mean a literal switch, of course. Since it involves a PWM system, I'm assuming it's not just an on-off arrangement, so the custom control would have to make use of a microcontroller that could properly implement the duty cycle phase-in/phase-out portion of the shift sequence. If the timing of this sequence is fairly reliable, however, then it seems like it could be duplicated easily enough. The factory control could either be supplied with dummy inputs to convince it that the bus is actually in 5th gear while the custom module moves it in and out of 6th, or it could be replaced completely, depending on preference.

Like you, I don't know enough about it to know if that is feasible but it sounds good.


I would prefer a reprogramming to get 6th but if the only way I can get it requires flipping a switch that takes me from 5th to 6th at highway speeds I would be ok with that.

[cadillackid]

wonder if you could send the TCM to someone like cummins allison conversions or such.. theres another one I was talking to and cant remember the name.. and just have the TCM programmed off the bus rather than deal with the manufacturers...

-Christopher

[PNW_Steve]

Originally Posted by cadillackid

wonder if you could send the TCM to someone like cummins allison conversions or such.. theres another one I was talking to and cant remember the name.. and just have the TCM programmed off the bus rather than deal with the manufacturers...

-Christopher

I tried one outfit that does that and they responded that they only do 1000/2000 Allison's. I will keep looking.

Thank you Christopher.

[lucasd]

I did some digging around and found a reference which might be useful in an effort to reverse engineer the controls.

I have attached an excerpt from a chapter about electronic transmissions which goes into some depth on the operation of the MD3000/MD3060 Allison series and its WTEC II control system.

It describes the inputs which are considered when the transmission makes a shift up or down in gears.

A very interesting bit is this chart which demonstrates visually how the transition between gears is made in terms of PWM control signals to different groups of solenoids.

The accompanying text makes it sound pretty involved, but the gist seems to be that the initial phase of de-powering the current solenoid and giving 100% to the new solenoid is a predetermined process that does not vary, so that's simple enough (relatively speaking...).

The next phase, however, actually reads some data to work. It monitors the speed of the input and output shafts and makes some kind of dynamic adjustments to the duty cycle of the oncoming gear's solenoids. When the ECU detects that the turbine speed is equal to the output speed times the gear ratio, then it uses that to conclude the shift has been completed properly and switches the new gear's solenoids on to a predetermined "hold" level. Once all that is done, the ECU just sits there in a holding pattern continuously checking its various inputs to look for a speed drop or some other signal indicating that it needs to shift again.

So! One question that emerges is, how important is this dynamic adjustment that occurs during the closed-loop phase of the shift - the bit after the initial signal and before the new holding phase? Do we know what these mysterious calculations are that the ECU is using to seek an "optimal" shift pattern, and how much do they actually matter if the bus is already at the proper speed and RPM range to conduct a shift from 5th/6th gear?

The other question is, can we tap in to the signals that the ECU is reading to monitor turbine and output speeds? I don't know - yet. That will take some more research... though if someone already has a solid understanding of the sensors being used or the communication protocol that would be needed, feel free to chime in!

Edit: An initial check on the matter seems to imply that they are just some kind of optical based speed sensors. If they work like most speed sensors, and transmit a predictable X pulses at Y RPMs, then we could interface with them via optoisolators, count the pulses to determine the speeds of the input and output shafts, and use a lookup table to know when the vehicle's speed is at an appropriate spot to up or down-shift. Some additional calibration to the table could probably be done if we could also tap in to the throttle position sensor and detect whether or not the driver was trying to accelerate.

A J1939 hookup might alleviate the need for a direct wire interface with the sensor returns, but given the relative obscurity of the protocol compared to the more common OBDII based stuff... it might actually be easier to just build the interpreters from scratch.

[Elliot Naess]

Greek to me. But considering that some Doritos-addict 19-year-old in his mother's basement in Leningrad can probably read my pulse right now... it must surely be doable.

And simplifyable. The User Manual for the 3060 scares the hiccups out of me.

[Clayton]

Originally Posted by Elliot Naess

Greek to me. But considering that some Doritos-addict 19-year-old in his mother's basement in Leningrad can probably read my pulse right now... it must surely be doable.

And simplifyable. The User Manual for the 3060 scares the hiccups out of me.

Is this manual available online?

[lucasd]

Originally Posted by Clayton

Is this manual available online?

There is a nearly 400 page troubleshooting manual available here:
http://ww2.justanswer.com/uploads/HE...e-shooting.pdf

The item I pasted the graph from earlier was a textbook on commercial vehicle repair. The chapter on electronic transmissions, which just happens to feature the Allison series and the WTEC-II control systems, is available as a freely downloadable sample here:
http://samples.jbpub.com/97812840411...41163_CH46.pdf

I'd attach the files here to make it easier, but they're both too big to upload to the board.

While large, the manual does have some nifty stuff in it, like this solenoid/clutch position chart, which shows us the activation patterns needed to reach various gears:

[Elliot Naess]

Originally Posted by Clayton

Is this manual available online?

Hmmmm.... Dang.... Could have sworn I saved it. But now I cannot find it. I'll keep looking. Probably came from this forum.

[Elliot Naess]

Here we go. This may or may not be the one I saw earlier:

http://www.wanderlodgeownersgroup.co...t=OM2157EN.pdf

[Rusty]

Originally Posted by lucasd

There is a nearly 400 page troubleshooting manual available here:
http://ww2.justanswer.com/uploads/HE...e-shooting.pdf

Thank you for that PDF- much easier to search than hard copy.

What about these ebay laptops? If we all kicked-in and shared the setup??

Allison Transmission Diagnostic Laptop Kit DOC DPA5


interesting, as well. they sell cables for specific applications
TCS Multidiag pro+ VCI OBD2 Diagnostic Scanner with Bluetooth instead of Autocom

[lucasd]

Originally Posted by Rusty

What about these ebay laptops? If we all kicked-in and shared the setup??

That seems pretty steep if all you want is the software. The DOC program is "only" $700.
http://www.diesellaptops.com/Allison...LLISON-V13.htm