Thomas Followed Me Home Today

[Brewerbob]

Originally Posted by Twigg

Has anyone ever managed to unlock a Blue Bird transmission?

I don't see how there would be two separate languages on the tranny.

Originally Posted by NHTSA

102 were pedestrians...
Nearly two-thirds (64%) of the school-age pedestrians fatally injured in school-transportation-related crashes were struck by school buses
or vehicles functioning as school buses (2006 to 2015).

I'm willing to bet that 90% of these pedestrians were killed at less than 15mph (as the bus is approaching, pulling away, turning into a parking lot). Should only need one gear to top out at 10mph (the more reasonable lockout speed).

[Twigg]

Originally Posted by Brewerbob

I don't see how there would be two separate languages on the tranny.

Well the trannies are the same. My question was whether or not anyone has persuaded Blue Bird to authorize the change.

[Brewerbob]

Originally Posted by Twigg

Well the trannies are the same. My question was whether or not anyone has persuaded Blue Bird to authorize the change.

Same thing; why the hell am I talking to Blue Bird or Thomas for an Allison tranny? I'm going to an Allison authorized dealer. <-- And that's assuming I can't find an independent truck shop.

[Twigg]

Originally Posted by Brewerbob

Same thing; why the hell am I talking to Blue Bird or Thomas for an Allison tranny? I'm going to an Allison authorized dealer. <-- And that's assuming I can't find an independent truck shop.

Nope ... you are not going to an Allison authorized dealer without Allison first giving permission. Allison will not do that without a letter from the OEM.

The dealers cannot simply "unlock" 6th gear. The process is that Allison provides the dealer with a one-time link that they use to download a new program that they flash to the ECU.

If you find an independent shop that can rewrite the software in the ecu, then you need to make sure they know exactly what they are doing. The software controls all the shift points and clutches. If they get it wrong your transmission could very easily grenade itself.

[Brewerbob]

Originally Posted by Twigg

The dealers cannot simply "unlock" 6th gear. The process is that Allison provides the dealer with a one-time link that they use to download a new program that they flash to the ECU.

Screw that. Chris, get busy.

Replace 6th gear shift point > 999mph with 6th gear shift > 55mph.*

Feel free to convert to kmh, rpm, or whatever other unit of measure you need.

[Twigg]

Progress ...

Removed a few more screws. Removed surround and vinyl from rear wheel well. No rust. Happy about that. It's a bit too cold to be unscrewing stuff.

SO as mentioned before, this bus has a mechanical engine so no ECU to break, and no information either.

What it does have is a long row of idiot lights as part of the Kysor VIP or AV1000 monitoring system. The problem is that since I have had the bus it hasn't worked, and I have been without basic indicators, like High Beam light and Flasher indicators ... and other minor stuff like coolant warnings.

So I am poking around behind the dash panel, as you do, and I spot a disconnected wire. Not unusual, there are disconnected wires all over the place from where the School Bus stuff was disabled.

But this one is marked "Ground". Ahh, lets ground it and see what happens.

What happened is that the dash lit up like a Christmas tree, very seasonal I thought. All my idiot lights are now working and the only one lit when it shouldn't be is the ABS warning light. I figured, the lights on the Bendix ABS controller were already telling me that the system needs some attention.

In other news ...

There is an air leak from the auxiliary system. Brakes remain aired up for days but things like the front door are losing air rapidly. There is a tank towards the rear and it is blowing air out of a valve at the bottom. It's not urgent, but it will need fixing.

[Brewerbob]

Nice tho I'm not sure these buses don't leave the factory with the ABS lights working. Mine said front passenger. Took the sensor out and it was FUBARed but a new one didn't make the light go out either. Haven't taken the wheel off or gone any further. Best I can tell, the brakes feel fine.

[Twigg]

So I finally managed to find the engine data plate. It was hiding under a bunch of other stuff. It has a big gash worn in the middle of it but the essential info was clear as day.

Engine is 250 hp and governed at 2200 rpm.

Now I have actual numbers I can consider asking Thomas for permission to unlock 6th gear. Thomas also sent me the Tire Listing from the original Bill of Materials, and that's what they will use when considering my request.

So I averaged out the tire diameter from those listed and am working with 41.5"

Final Drive Ratio is 5.38

The numbers are as follows:

At max engine speed of 2200 rpm:

1st ... 14.47 mph
2nd ... 27.14 mph
3rd ... 35.81 mph
4th ... 50.49 mph
5th ... 67.32 mph

6th ... 77.67

Those are maximum speeds in each gear, not shift points.

More importantly, opening up 6th gear would give me a cruising speed of 63.55 mph at 1800 rpm, and that's about perfect.

With that maximum speed only 2.7 mph above the speed-rating of the tires at maximum Load Index (which never happens), I can see no good reason why Thomas would deny the request.

Thomas have a good track record in this matter, so I am hopeful.

[EastCoastCB]

If its a real concern, there are M rated tires available.
Or just over-inflate by 5 psi.

[Twigg]

Originally Posted by EastCoastCB

If its a real concern, there are M rated tires available.
Or just over-inflate by 5 psi.

I'm hoping that Thomas don't have any real concerns. I did hear that they start getting jittery around 75 mph. Common sense suggests they would offer leeway up to 80 mph, but common-sense isn't always a corporate policy.

All I can do is ask.

[david.dgeorge07]

I think most of the commenters on this thread have been able to read my build thread, but as somebody who has been down the road of getting 6th gear unlocked I have a few things to add. While Thomas had a slow turnaround and generally gruff attitude they were helpful and workable. But their letter will not authorize unlocking a transmission gear that will allow the vehicle to go in excess of 75. I don’t know if that’s negotiable or not but it is my sense is that it is non-negotiable. Allison was actually more difficult to work with than Thomas. Allison required Thomas to furnish data on the bus as to what the final gear ratio and top speed of the bus would be in the event that sixth gear is unlocked. They were unwilling to authorize the change in the event that the bus go faster than 75 mph. In my case the letter had to be modified by Thomas to mandate that the vehicle speed limiter be employed to keep the vehicle from going faster than 75 mph. Allison was the one who was quite picky. They have a new guy on staff there in charge of releasing the CIN codes and apparently he is much less lenient than his predecessor. It is not as simple as going to an independent shop because they cannot do the work without the authorization code from Allison. Also it is more complex than simply unlocking sixth gear it’s a full reprogramming of the TCM module which updates all of the shift points for your specific vehicle application. The only way an independent shop would be able to help you without Allison’s consent is if they have the proper computer and you can find a CIN code from someone with the same drivetrain.


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[Twigg]

Originally Posted by david.dgeorge07

I think most of the commenters on this thread have been able to read my build thread, but as somebody who has been down the road of getting 6th gear unlocked I have a few things to add. While Thomas had a slow turnaround and generally gruff attitude they were helpful and workable. But their letter will not authorize unlocking a transmission gear that will allow the vehicle to go in excess of 75. I don’t know if that’s negotiable or not but it is my sense is that it is non-negotiable. Allison was actually more difficult to work with than Thomas. Allison required Thomas to furnish data on the bus as to what the final gear ratio and top speed of the bus would be in the event that sixth gear is unlocked. They were unwilling to authorize the change in the event that the bus go faster than 75 mph. In my case the letter had to be modified by Thomas to mandate that the vehicle speed limiter be employed to keep the vehicle from going faster than 75 mph. Allison was the one who was quite picky. They have a new guy on staff there in charge of releasing the CIN codes and apparently he is much less lenient than his predecessor. It is not as simple as going to an independent shop because they cannot do the work without the authorization code from Allison. Also it is more complex than simply unlocking sixth gear it’s a full reprogramming of the TCM module which updates all of the shift points for your specific vehicle application. The only way an independent shop would be able to help you without Allison’s consent is if they have the proper computer and you can find a CIN code from someone with the same drivetrain.


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Thank you. I knew all of that but it would probably help someone else reading.

In part it depends on the diameter of the tires. I chose a mid-point to calculate that, and it only applies to brand new tires.

If I, or Thomas can be persuaded to use a very slightly smaller diamerter, then the 75 mph barrier will not be breached.

It's harder to govern mine to a set speed because the engine is all mechanical.

I have no idea why Allison would be so damned picky. They supply plent of transmissions for vehicles that can exceed 80 mph, and Thomas sells buses that can do the same right from the factory.

Given the much lighter loading on an RV conversion, there are no good arguments to refuse.

[david.dgeorge07]

Originally Posted by Twigg

Thank you. I knew all of that but it would probably help someone else reading.

In part it depends on the diameter of the tires. I chose a mid-point to calculate that, and it only applies to brand new tires.

If I, or Thomas can be persuaded to use a very slightly smaller diamerter, then the 75 mph barrier will not be breached.

It's harder to govern mine to a set speed because the engine is all mechanical.

I have no idea why Allison would be so damned picky. They supply plent of transmissions for vehicles that can exceed 80 mph, and Thomas sells buses that can do the same right from the factory.

Given the much lighter loading on an RV conversion, there are no good arguments to refuse.

Thomas will ask you what tires you are running before they write the letter. They didn't ask for documentation though.

All of the reluctance is because of liability. If you get in a wreck and they haven't done due diligence as to the original engineering of the vehicle's speed worthiness, they could get sued.


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[Rusty]

https://www.youtube.com/watch?v=EpmN...ature=youtu.be

Term explained: CIN(Calibration Identification Number) - a sticker on the side of the ECU.

Try these guys if you run into dead-end w/ 6th gear.

Transmission Instruments

Video of Allison software in action

https://www.youtube.com/watch?v=EpmNjMnRrVY

[Twigg]

Originally Posted by david.dgeorge07

Thomas will ask you what tires you are running before they write the letter. They didn't ask for documentation though.

All of the reluctance is because of liability. If you get in a wreck and they haven't done due diligence as to the original engineering of the vehicle's speed worthiness, they could get sued.


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Several of the tires on the BoM that Thomas sent me have a diameter of 41". That would reduce the maximum speed to 76 mph ... and that when the tires were brand new only.

In fact, the 295/75R 22.5 go as low as 40" ... Top Speed then 74.86 mph.

Ha! Guess what tires I am running

[Twigg]

Originally Posted by Rusty

Term explained: CIN(Calibration Identification Number) - a sticker on the side of the ECU.

Try these guys if you run into dead-end w/ 6th gear.

Transmission Instruments

Video of Allison software in action

I don't have an ECU. I have a 6CTA8.3 - 250

It's one of the last of the all mechanical 8.3L engines.

[david.dgeorge07]

You do have a TCU though. That is where the CIN actually is.


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[Twigg]

Originally Posted by david.dgeorge07

You do have a TCU though. That is where the CIN actually is.


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Oh yes. That was an interesting video.

As I understand the process, Allison write a new program for the specific vehicle then send the tech a one-time link to download it. He then uses that software to flash the TCU ... and the new program actually resets all the change-points as well as unlocking 6th gear

[cadillackid]

TCM in allison terms.. and you can always get a completely programmable TCM like how I did mine.. i can change every shift point, the TAP pressure gradients, employ multiple shift patterns based on a switch input..

I was tired of allison's BS when it came to all of this... probably cost me a little more but if I dont like when my 5th gear engages i can simply pull over, alter the curve, and be on my way.. .

I realize lawyers run this country but.. im one of those peoiple that feels as if i bought it i should be able to do what i want with it ..

the fact Navistar wont let me change 3 parameters in the ECM of my T-444E has me totally ticked off.. actually they havent said they wont let me.. they just have never heard of anyone building a custom school bus with non-factory parts.. so they "have no idea" how to proceed.. basically my case wont fit in their compurter-form of how to open a service case file to change the 3 parameters...
I even own the software.... and the subscription rto navistar.

similar sysatem to allison releasing a CIN.. has to be done at the top level...

-Christopher

[Twigg]

Originally Posted by cadillackid

TCM in allison terms.. and you can always get a completely programmable TCM like how I did mine.. i can change every shift point, the TAP pressure gradients, employ multiple shift patterns based on a switch input..

I was tired of allison's BS when it came to all of this... probably cost me a little more but if I dont like when my 5th gear engages i can simply pull over, alter the curve, and be on my way.. .

I realize lawyers run this country but.. im one of those peoiple that feels as if i bought it i should be able to do what i want with it ..

the fact Navistar wont let me change 3 parameters in the ECM of my T-444E has me totally ticked off.. actually they havent said they wont let me.. they just have never heard of anyone building a custom school bus with non-factory parts.. so they "have no idea" how to proceed.. basically my case wont fit in their compurter-form of how to open a service case file to change the 3 parameters...
I even own the software.... and the subscription rto navistar.

similar sysatem to allison releasing a CIN.. has to be done at the top level...

-Christopher

Christopher ..

Are you saying you can reprogram the Allison TCM on the MD3060 to set new shift points and unlock 6th gear?

If you can, and if Thomas and Allison proved awkward, then we can talk about a fee