[MrE]

I feel like an idiot because I don't know the answer to my question. I own a 1986 all mechanical Newell. It had the DD 8V92 and Allison HT740 transmission.  Long story short, I decided to replace the drive train. I bought a Denver RTD 2000 transit bus with a Cummins ISM and ZF Ecomat 2 transmission for a driveline swap. It came with an I/O Controls Dinex G multiplex system. For those interested, it's a 2000 Orion V with a Cummins ISM and ZF Ecomat 2 HP HP592C transmission.

We've got the ISM and ZF transmission in the 86 Newell, but not getting the transmission to shift into any gear. The Newell is in Missouri and I'm in Boise Idaho. I've got bids, and it's $7500 to tow it to Boise for me to diagnose. My alternative is to drive my Range Rover to Missouri with adequate tools to diagnose the problem.

To my knowledge, all I need is the transmission ECU and engine ECU communicating with J1939 CAN bus for it to work. Fortunately, J1939 is relatively standardized, unlike auto manufactures with their CAN bus messages. I have the tools to monitor the CAN bus messages, but want to make sure that if I load up my Range Rover with my tools and monitoring software I'll be able to get my coach operable.

Obviously with my 1986 Newell I don't need a PLC logic ladder to prevent me from pulling away from the curb because my non-existant wheelchair ramp is extended.

[bikestuff]

I doubt many of us have undertaken such a bold project...but the thought crossed my mind and I thought I would share.

On my coach (Cat C12 and Allison 6 speed) there are several things that will prevent the transmission from going into gear. The one that most often gets me is the engine in fast idle. No error message just a flashing 6 when I try to go into gear.

So...my thought is that it might not be a CAN message...rather a simple input that may be keeping you from working.

FWIW
bill

[MrE]

Thank you Bill for the input. It's not the fast idle. There are certain functions that I know will prevent the shifting of gears, one is it the airpressure isn't high enough. The donor coach has an airpressure sensor that goes to ground if the air pressue is adequate and I believe that is wired in to the 86 Newell.

[Richard]

Not trying to be a smart aleck, but what is your question?

Are you asking if you should go a diagnose yourself vs paying to have it towed? If that is the question, my opinion is to avoid the tow at ALL costs. The potential for coach damage is far too high for me to accept that risk.
Or are you asking if any of us have specific knowledge of how the ISM and ZF talk to one another? YOu might have better luck posting your question on one of the bus conversion forums such as bus nuts on line, or BCM

[MrE]

My question is "To my knowledge, all I need is the transmission ECU and engine ECU communicating with J1939 CAN bus for it to work". Seeing as I can't use the donor bus as an example because of it's multiplex system, and can't use the Newell as an example because it was all mechanical, is there another component required for the two ECUs to talk? My Range Rover uses CAN bus, and it's probably got about 30 units conversing over the CAN bus talking to each other. If my seat belt isn't fastened it's a CAN bus error, if a taillight is out it's a CAN bus error.

Just want to make sure that I'm not headed back there without something necessary.

[Floridian]

From past experience CAN on buses it won't be just a single message, it is a group of different messages that will allow something to happen. 

In your case you should think about gear selection (think about it, if the transmission is already in first gear why change it to first gear? or if it is in reverse you can't just change it to first if the revs are min. X, or > X) it all depends on the computer for you to be able the trans to do what you want. You'll need the original ECU and everything connected, filter those ECU's and then see what are they interchanging at the time whatever device you need to control.

My experience comes from using BMW iDrive controls on my legacy coach to change gears (I detect the CAN bus messages when any of the iDrive devices do something and then act on my old newel like it used to with a button).

I used a CAN bus to USB tool that helped a LOT to decode some messages but some other ones were really obscure (for example, BMW will physically move the gear stick if you send a specific message or if a certain condition is met).

If there's anything I can help with let me know but unless this is some very basic CAN buses and ECU's it will take more than just those two talking to each other.

[MrE]

@Floridian, we're on the same page, just going at if from different directions. My goal is to have a digital dash and a smart steering wheel. Easiest way to accomplish that is to use CAN bus. VMSpec does a Windows based digital dash, but only works with an Allison transmission. I undestand that Torque Pro, an Android ap, works with the J1939 protocol now. I don't have the coach local so I can't test.