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Old 05-23-2022, 12:39 PM   #1
Mini-Skoolie
 
Join Date: May 2021
Location: Olympic Peninsula, WA
Posts: 11
Year: 1998
Coachwork: Thomas
Chassis: International 3800
Engine: T444E
Pre-1998 T444E Transmission Options

Hi folks,

I've been lurking a while here and a few other places like pirate 4x4 looking for possible transmission options. I've got a '98 Thomas 3800, which unfortunately was built on a '97 chassis - so I'm a year off from having J1939 support from the ECM.

My current plan is to throw a cooler on the 545 and run it until it blows. But I'm trying to plan out what will go in there when that happens.

Obviously I could attempt a 643(with great difficulty) or a Spicer 5-speed. But I'm curious if anyone knows options for the MD3060 or the A-2000.

I've found conflicting reports on the 3060 - some saying it requires J1939, and others indicating there were TCMs that ran off J1708. So far I've seen J1939 and "AUTODETECT" stamped TCMs for sale and I'm not positive what that autodetect means.

I'm also curious if anyone has experience with the J1708 -> J1939 converters:

https://c-a-i.net/translators/j08
https://copperhilltech.com/mastercan...j1939-gateway/

Looking at the documentation - they convert throttle position, engine load, road speed, etc messages. I can't think of much else the transmission might need - so I'm curious if anyone has experience there. I can't imagine the transmission NEEDS the faster baud rate of J1939.

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Old 05-23-2022, 03:48 PM   #2
Bus Crazy
 
Join Date: May 2018
Location: topeka kansas
Posts: 1,370
Year: 1954
Coachwork: wayne
Chassis: old f500- new 2005 f-450
Engine: cummins 12 valve
Rated Cap: 20? five rows of 4?
my example

2007 2400pts

there is an engine rpm sensor in the transmission -- it looks at the torque converter rpm.

drive shaft rpm sensor is at the tail of the transmission... I assume the TCM programming has stuff like rear end gear ratio and some thing to do with tire sizes

To me it looks like there is a third rpm sensor in the middle of the transmission.. I assume it has something to do with being able to see if the transmission is shifting gears.........

My engine is a mechanical injected cummins -- there are no electronics to interface with.

The mechanical injection cummins 8.3 is found with the 3060 and that had no electronics.... so from talking with Jason at transmission tuners.....

I will have to wire in some parts from a harness... He preferred to use a new TCM. So, there is the ability to use this transmission with an engine that is all mechanical.

CadillacKid is the fellow that forged the path for people like us here on the forum. I am just following along his path.

william

william
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Old 05-23-2022, 09:23 PM   #3
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 16,725
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
the AutoDetect TCM is your best bet, or you can get a throttle box from CAC (or i believe jason at transmissiontuner dot com)..


the box I originally got from CAC (and still have in a drawer).. took the voltage reading from my drive-by-wire pedal and converts it to J1939..



that was what I used before I enabled and connected my J1939 link, it didnt affect my normal drive-by-wire operation.



the other method you could go is to forge your own mechanical cable-pull and use a mechanical-to-J1939 throttle box. sold by CAC and Jason also I believe... these equate an amount of cable pulled from the box to a J1939 throttle reading...



I havent used a J1708 to J1939 converter although as long as it sends throttle data it would be an option.. I built one but cant remember what I was going to use it for..



supposedly the WTEC-II TCMs were built to use J1708 as the throttle input.. at least some of them.. many of them used an analog throttle (a TPS sensor that sent a return voltage based on position).. I have next to no experience with WTEC-II stuff so i havent tested..



this is one of CAC TPS units for mechanical use..



https://www.caconversions.com/cac-th...osition-sensor


they also make an electronic version.. the one I have and had connected to my 444E prior..



the all analog throttle and auto-detect TCM are often CAT throttles.. as caterpillar was the first to install electronic transmissions on the electronic engines.. the 8.3 was a favorite to get the 3000 series and the 3116 / 3208 saw a few as well..



if you are going 6 speed 1000/2000, then I doubt you'll find many TCMs that are auto detect. most will be J1939..



again I have ended up forgin my own path to get to my beautifully shifting and responding set up.. everything from engine mods to trans tuning, boards, etc..



when thinking about how this stuff works, cruise control is another issue altogether.. as the pedal stays at 0% when on cruise in a T444E.. which can create a host of issues from no downshifting to shifting in a non modulated state.. this is why I went J1939 and enhanced the data stream to feed the TCM as much cruise info as i could, if you dont use the cruise control then its probably a noin issue for you.
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Old 06-26-2022, 09:57 PM   #4
Mini-Skoolie
 
Join Date: May 2021
Location: Olympic Peninsula, WA
Posts: 11
Year: 1998
Coachwork: Thomas
Chassis: International 3800
Engine: T444E
Thanks for all the info folks. Sorry it's been a sec - been away for work for quite a while.

Found some interesting reading here from folks reversing the GM TCMs (taking a PWM TPS input instead of j1939) https://www.4btswaps.com/threads/the...-thread.15428/

Curious what kind of j1939 cruise data you're able to send to the transmission for cruise?(I haven't bought the spec yet and haven't found a free download, so don't have the full list of messages)

I'd been contemplating cruise control too and thinking about having a MITM unit between the TPS and the transmission (isolated from the TPS signal heading to the engine for safety) that would use the J1708 Engine Load message as a proxy for throttle position whenever cruise is on. And hope that it gives stable results.
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Old 06-26-2022, 10:11 PM   #5
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 16,725
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
Quote:
Originally Posted by j2d2 View Post
Thanks for all the info folks. Sorry it's been a sec - been away for work for quite a while.

Found some interesting reading here from folks reversing the GM TCMs (taking a PWM TPS input instead of j1939) https://www.4btswaps.com/threads/the...-thread.15428/

Curious what kind of j1939 cruise data you're able to send to the transmission for cruise?(I haven't bought the spec yet and haven't found a free download, so don't have the full list of messages)

I'd been contemplating that and thinking about having a MITM unit between the TPS and the transmission (isolated from the TPS signal heading to the engine for safety) that would use the J1708 Engine Load message as a proxy for throttle position whenever cruise is on. And hope that it gives stable results.

yep ive done it.. ive build a MITM J1939 box to manipulate the parameters going to my allison... I have not played with actual throttle control via a box but im sure i could do it.. I did set the high idle by becoming the module ID for an auxilliary throttle control such as an RE bus would have and sending a setpoint... but never on the road.. i have no need and could cause real issues..



anyway i cant remember the PGN / SPN numbers for the cruise data, however the ECM sends to the TCM that cruise is engaged and sends the setpoint data.. the TPS signal for the trans directly matches the engine load factor... the other paranmeter that gets sent which the allison responds to much quicker is a kickdown request which drops the transmission down a gear.. this request gets released to 0 when the overload factor is cleared down.. seems to be load factors less than 75% or so..



depending on your TCM you can also emulate module ID 5 which is the allison standard for a digtal shift-pad and then you can up/down shift at will and set your maximum gear range..



manipulating the throttle data to the trans wont hurt.. it wont downshift into a dangerous gear as the TCM has a maximum RPM..



on my tuneable TCMs that RPM is programmable by me... non tunable TCMs that RPM is factory set and stamped on the TCM..


someplace in one of my threads i talked about reading and parsing J1939 data and code I played with..



I have the spec but its too big to upload to the bard so ive never sent it here
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