Adding J1939 to a 3 box for allison swap

[nikitis]

Originally Posted by Bouje bus

Drove the bus from Phoenix to Greer Arizona for Labor Day. handled the mountains like a champ!!!!
down shifting actually slowed the bus when needed. some of the longer pulls got down to 43 mph. way better than with the 545. it does seem to hang onto taller gears longer than i'd like. occasionally i'd manually downshift just to keep the RPM up.

she likes to cruise at 63.
very happy

nikitis your diagram exactly matches my wiring set up.
i've got a scan guage plugged into the 1708 port. i was watching throttle %, RPM, Water temp, and speed. cant believe the speed is still accurate post swap.

Did you have to change out your throttle at all, or do you even have to touch it?

[nikitis]

Found this newly released video of a guy doing the engine hp tune on the T444E using the cheap chinese clone nexiq.

Fun vid to watch. He slipped his torque converter like I did when he upped to 230 HP.

https://www.youtube.com/watch?v=213iU7W9yyc

[tatersalad812]

Originally Posted by Bouje bus

two different troubleshooting guides have said 2 120 ohm resistances in parallel to generate a 60 ohm load across yellow/green.

i measured and got 2.5v on high side, 1.79 on low side.
physically i think the network is solid.

is the address request going unanswered from the AU box, or the TCM?

Any canbus device that transmits requires termination resistor. If its just listening it doesnt require a resistor but it also wont hurt anything if you have it. Ive got a pretty decent background in canbus if anyone needs help. If anyone needs a cheap canbus sniffer let me know they are easy to build.

[nikitis]

Originally Posted by tatersalad812

Any canbus device that transmits requires termination resistor. If its just listening it doesnt require a resistor but it also wont hurt anything if you have it. Ive got a pretty decent background in canbus if anyone needs help. If anyone needs a cheap canbus sniffer let me know they are easy to build.

Actually can you read and reply to this post here tatersalad812?
https://www.skoolie.net/forums/f49/j...tml#post516198

[mangus580]

Very cool stuff!

Looking into a 2000 swap for my bus, and I know it being a 97 it should be a 3 box setup, but whats the easiest way to confirm?

[cadillackid]

Originally Posted by mangus580

Very cool stuff!

Looking into a 2000 swap for my bus, and I know it being a 97 it should be a 3 box setup, but whats the easiest way to confirm?

does your bus have a large computer hanging off the passenger side valve cover? if so then its a single box and may have a J1939 connector...

[nikitis]

3 box ECM is behind the firewall, driver side with a large rectangular plug in the engine compartment connecting to it through the firewall. ECM is under the dash far left side tuck well into the dash.

[nikitis]

Ok Update, I've learned a lot since August of 2024 on this thread, and I've been contemplating my AT545 to AT1000 6 speed upgrade a lot.

As cool as the Au device is, I think I'm going to go with a CAC solution. I called them to get my options and here is what they told me. I double clarified each item with them to be sure they understood what I was asking.

They said that an Allison 1000 does not even need to talk to the ECM of the 3 Box, and it will work fine as long as it has the right tune in the TCM, and that we don't have to lose cruise control.

They also stated they may or may not have to replace/modify the TPS, it would depend on what they see. But they've done over 15 buses like mine they've said and all have maintained cruise control ability, which I'm growing fond of after having done 2 recent trips, but some 3 box's they did not have to replace the TPS and some they did. Not sure what the difference here is.

Regarding the tune of the TCM. The TCM is still used by the transmission but can receive values another way than talking to the ECM, similar to the Modulator on the AT545, but using that signal to the TCM itself. In this way, you can use an AT1000 like a mechanical transmission and it will shift properly if you have the right TCM programming. They have several profiles for tuning from Allison themselves that can handle this they said. It's not custom, and is official. Allison apparently has the capability to run modern Transmissions as mechanical, but isn't commonly used but CAC has access to the tunes.

They asked me questions about what my T444E is governed at currently. I told them, I can modify the governor in the ECM, I have that capability. (they were a little surprised by that but they said okay, set it to 2800 RPM) I asked them what's better? a 2300 RPM tune or a 2600, or a 2800 RPM Tune?

They recommend if I can program the governor to 2800 RPM they have a proven great shift pattern for the 3 Box buses tuned for full throttle at 2700 RPM and that with that tune, I would be achieving 65 MPH at only 1600 RPM, and by 2700 RPM, I'd be puckering up at 80+ MPH. And they also recommend I install an upgraded 3 phase torque converter since it's a BUS and it would be better for it due to weight distribution reasons with the AT1000, which without one may be why we've know buses doing this have poor shifting capability.

I know this will be a more costly route, but they do the install, and I have peace of mind.
I'm not that mechanically ready to deal with something of this magnitude, and I'd prefer to have them do it since they seem to be pros at it, sounded confident, and has been doing it since the 80's.

Also, regarding the AT1000, I asked if I should get it overbuilt, and they said unless you plan to be up in the 38,000 lb range it's not needed. I told them I will likely end up in the 26,000-28000 lb range, and they said absolutely not needed to be overbuilt, a standard AT1000 will be fine for your application and could pull a car behind you still.

Thoughts?

[Albatross]

Originally Posted by nikitis

Ok Update, I've learned a lot since August of 2024 on this thread, and I've been contemplating my AT545 to AT1000 6 speed upgrade a lot.

As cool as the Au device is, I think I'm going to go with a CAC solution. I called them to get my options and here is what they told me. I double clarified each item with them to be sure they understood what I was asking.

They said that an Allison 1000 does not even need to talk to the ECM of the 3 Box, and it will work fine as long as it has the right tune in the TCM, and that we don't have to lose cruise control.

They also stated they may or may not have to replace/modify the TPS, it would depend on what they see. But they've done over 15 buses like mine they've said and all have maintained cruise control ability, which I'm growing fond of after having done 2 recent trips, but some 3 box's they did not have to replace the TPS and some they did. Not sure what the difference here is.

Regarding the tune of the TCM. The TCM is still used by the transmission but can receive values another way than talking to the ECM, similar to the Modulator on the AT545, but using that signal to the TCM itself. In this way, you can use an AT1000 like a mechanical transmission and it will shift properly if you have the right TCM programming. They have several profiles for tuning from Allison themselves that can handle this they said. It's not custom, and is official. Allison apparently has the capability to run modern Transmissions as mechanical, but isn't commonly used but CAC has access to the tunes.

They asked me questions about what my T444E is governed at currently. I told them, I can modify the governor in the ECM, I have that capability. (they were a little surprised by that but they said okay, set it to 2800 RPM) I asked them what's better? a 2300 RPM tune or a 2600, or a 2800 RPM Tune?

They recommend if I can program the governor to 2800 RPM they have a proven great shift pattern for the 3 Box buses tuned for full throttle at 2700 RPM and that with that tune, I would be achieving 65 MPH at only 1600 RPM, and by 2700 RPM, I'd be puckering up at 80+ MPH. And they also recommend I install an upgraded 3 phase torque converter since it's a BUS and it would be better for it due to weight distribution reasons with the AT1000, which without one may be why we've know buses doing this have poor shifting capability.

I know this will be a more costly route, but they do the install, and I have peace of mind.
I'm not that mechanically ready to deal with something of this magnitude, and I'd prefer to have them do it since they seem to be pros at it, sounded confident, and has been doing it since the 80's.

Also, regarding the AT1000, I asked if I should get it overbuilt, and they said unless you plan to be up in the 38,000 lb range it's not needed. I told them I will likely end up in the 26,000-28000 lb range, and they said absolutely not needed to be overbuilt, a standard AT1000 will be fine for your application and could pull a car behind you still.

Thoughts?

Sounds fantastic.

As much as I can enjoy hacking, sometimes it's better to simply sit back and let the commercial solutions work themselves. It seems a bit like over-promising, but depending on the price, I would give it a go.

[BamaBus]

Originally Posted by nikitis

Thoughts?

I would have folded a long time ago and had a new hand dealt.

[cadillackid]

unless CAC has some new magic...
there are 3 ways to get throttle info to an allison..

1. - BEST - Data link from an ECM to the TCM using J1939. - this method provides all datapoints to the transmission.. including TPS position, cruise control mode, cruise set speed, engine load factor, ECM MPH, and a bunch of other stuff that probably doesnt matter.


2. - Analog TPS to a TCM that has "analog or Auto" enabled. this is essentially a variable resistor connected to a cable or a rotary type TPS that you mount on your injection pump linkage (mechanical engine).. or mount to measure your pedal position electronic engine.. its advantage is you can adjust the geometry to affect shift points (which you cant program). the analog TPS may also go through a conversion box (CAC does this) whuich turns it into J1939 data for the TCM to recognize.. turf has this setup on his cummins.



3. - electronic monitoring of OEM TPS. - CAC does this.. they have a device which you tap into the existing wires of the accelerator pedal and their device rwads the voltages, and cnverts it to J1939 data which it sends to the TCM.


thise are the ways you get throttle data to the transmission..



I originally used #3 in my setup.. I still have the device. it worked fine.. did the job as intended except on cruise..


lets first talk about how ANY transmisison works when you drive... think of a stick shift... in a stick shift your brain is the TCM... you decide when to shift and how quick you let the clutch out, how high to run the RPM etc.. if you start climbing a hill you press further down on the accelerator.. you realize the vehicle isnt maintaining or accelerating so you downshift... then you get to the top of the hill and you upshift (assumuing its not a huge mountain.. im taliing regular driving)... your brain tells you the engine load is going up and you feel like its lugging so you downshift.. thrn you let up on the pedal and the vhicle sounds like its revving and you dont need that much power so you upshift and drop RPMs for the best flat ground cruise..till you hit a hill again..



Now lets talk about how any autmatic trasnsmission works.. from the Old turbo hydromatic on a gas engine all the way to the modern vehicles.. they monitored throttle position and / or engine load... on a gas motor as you loaded the engine the vacuum would go less and less .. the modulator in the transmission knew at closer to atmospheric that you must have the butterflies in the carb open wider so it would raise the upshift point..(my SV392 with AT540 is this way). and be more likely to trigger a downshift... it also raised the line pressure typically so that under heavier load the shifts would be tighter as to not slip and glaze the friction discs or warp the steel plates from excessive slippage..
on a diesel theres no butterflies so the transmissions used cables.. cables going to the injector pump linkage to raise and lower the modulation point... sometimes to the actual pedal itself.. a cable that actuated it mechanically.. (my DTA360 with MT643 is this way). in modern vehicles with drive-by-wire.. the computers do it all with data links..


now lets talk about cruise control.. and possibly some questions for CAC..


cruise control as anyone knows varies the engine power to maintain a set speed.. if you climb a hill it increases the engine power.. if going downhill it lets off... simple stuff..


anyne who is an old dude like me remembers cruise control on the older vehicles... it was an actual vacuum operated canister that had a cable connected to the carb linkage (or diesel injector pump).. you used to be able to see the pedal go up and down as it varied the engine power...


since the pedal was actually moving up and down , the autmatic transmission.. however it was connected behaved just the same as it would if you were driving with your foot... no different...



drive by wire engines... specifically International / navistar electronic engines...


the T444E (yes even the 3 box).. the DT466E.. the VT275/365.. the Maxxforce.. are all drive-by-wire engines... there is no physical linkage from your foot pedal to an injection pump... look at your pedal.. its just 5 wires.. no cables, no linkages, just 5 wires... (+5 VDC reference, ground, TPS return, and 2 for the Idle validation switch..)..


when you drive you press the pedal and drive it like anything else.. the TPS voltage varies telling the ECM to increase and decrease the engine power.... if you have an older auto transmision (545 / 643).. the computer can command an electric modulator to go to "high" (high shift points / kickdown).. or to "low" (low shift points / no kickdown).. its not great but it worked...
on cruise control.. watch your pedal.. it will stay up.. it doesnt move up and down... the computer internally adjusts the engine power to maintain your set speed.. your pedal just sits there.. since the computer controls the electronic modulator it can command a "high" / kickdown on an AT545 / MT643 via the modulator device,,, even on cruise...



if you have a modern J1939 connected 1000/2000/3000 then the computer tells the TCM all kinds of stuff including pedal position.. and cruise data.. the allison knows the desired speed, actual speed, engine power, etc.. even on cruise.. the engine load factor is sent to the TCM and so it knows when you are not making your cruise setpoint, and knows when its starting to lug and triggers a downshift.. when the TCM recognizes that cruise has been set it knows not to look at physical pedal position any more on an electronic engine as it will just be sitting there.. so it uses the other data..



lets talk CAC / transmissiontuner / PCS / Xcaliber / and any of the 3rd party setups for retrofitting an electronic allison into an older engine...


note above.. they monitor your pedal position.. your throttle input.. if your pedal is just sitting there how can any of them have a clue that you are on cruise control lugginga hill in 6th gear when you need 4th... eventually your bus slows down to a point where it would downshift anyway.. and then it drops a gear... (ie if you are decelerating in any automatic you slow down enough where it downshifts on its own with your foot off the pedal) thats what you get with these type of setups on cruise... the TCM has no idea.. the converter is locked in mid 2nd gear on up so it isnt able to monitor slippage to use as a method for determining torque input.. as far as the TCM knows your foot isnt even on the pedal.. you are just coasting...



so unless CAC has somehow incorporated a datalink into their box so it knows the engine load , or is monitoring the on / off state of the OEM modulator wires (that modulator doesnt fit any electroniuc transmission.. it is gone after the swap).. then tell me how any of these know how to properly shift under cruise... maybe they have something new.. but my redbyrd transformation thread went into a lot of detail about cruise control...


so i would ask CAC how does the TCM get proper throttle data on cruise when the pedal doesnt move... no pump to move either its all internal...


the mitigation to thius is you buy the TAP shift and you can manually up / downshift your transmission as it starts to lug down on a hill then you can tap it back up at the crest... otherwise i dont see how they can say it works properly with proper line pressure and modulation on hills.. you could also stomp the oedal to the floor on a hill too and it will downshift and raise line pressure...


again, i went through this when i built mine...

[nikitis]

Good points, and I don't disagree with you. I pretty much asked them that, and they didn't tell me how, but she said to stop reading the forums, cruise will work. When I speak to them again, I'll bring that up about how does the TCM know when your foot is off the pedal in cruise and see what they say. Before she said they have Allison TCM flashes from Allison that aren't common, and can handle it somehow. I don't know if that means they have extra input/readers for the Throttle for their solution and it translates it for them. I'm thinking they do but they sound damn confident over the phone it will not be an issue so I think they may have their own unique solution for it. She understood it was a J1708 ECM. I made that VERY clear, and explained that these buses only took mechanical transmissions, and even asked how does an electronic transmission talk to the J1708. Her response was this.

"The AT545 you have now is mechanical and works with cruize control" (yeah through the modulator which the AT1000 won't have) "We have a Allison flash that can make it work". And that was it. I'll pry more into that statement next I speak with them.

I think the missing piece here could be potentially Allison TCM's can talk to J1708's. Even Jason at Transmission tuners stated to me he has a TCM flash that can work directly on J1708 with his 4th gen. So it would seem maybe Allison does have a TCM flash to work with J1708 and can pull data from the ECM's? This may also be what CAC does.

Thanks for the assistive input and helping me negotiate better with CAC.

[cadillackid]

if they have a J1708 enabled TCM then you have basically the same functionality as a J1939.. cruise Data *IS* sent over the J1708 link.. and that would be the best scenerio for a 3 box as you. wouldnt need a converter..


if they have other inputs that somehow read that cruise has been enabled.. ie reads the switch presses (theres no cruise light to use).. then thats a possibility.. the way something like that could function is note the vehicle speed when the cruise set switch was enabled.. (they have data link from Their box to the TCM so they know the Output shaft speed of the allison).. and then they could see when the bus slows down.. ..they could send TAP down or even artifical TPS data to the TCM based on set speed vs desired speed deviation... the only data they need to know at that point is that cruise is on.. maybe the TAP shift screen they prpvide has a cruise on / off function for IH since there's no cruse light... if they have a real solution then it will likely work great..

[nikitis]

Ok, spoke to her this morning, she said they have a voltage read off of the throttle, and they have a kit device that reads that and converts it to what the transmission needs to know.

So with that, is it still a problem because if it's in cruise mode on, and the throttle is 0 will the transmission not function correctly and maintain cruise? Or is that voltage maintained when cruise is on regardless of the throttle position?


Also on another note. I'm shopping for a Allison 1000 core, 2006-2008, any pointers on where I can obtain one?

Additionally does it matter of they come off of a Mercedes or M45 Chassis, or Isuzu? I see a few for sale online but they all come from those 3.

[cadillackid]

Originally Posted by nikitis

Ok, spoke to her this morning, she said they have a voltage read off of the throttle, and they have a kit device that reads that and converts it to what the transmission needs to know.

So with that, is it still a problem because if it's in cruise mode on, and the throttle is 0 will the transmission not function correctly and maintain cruise? Or is that voltage maintained when cruise is on regardless of the throttle position?


Also on another note. I'm shopping for a Allison 1000 core, 2006-2008, any pointers on where I can obtain one?

Additionally does it matter of they come off of a Mercedes or M45 Chassis, or Isuzu? I see a few for sale online but they all come from those 3.

the voltage reader is what I used originally.. since the pedal stays up it always reads the voltage which applies to 0% throttle when cruise is on.. that was my big issue and why i set out to get my J1939 link working correctly..

[nikitis]

Originally Posted by cadillackid

the voltage reader is what I used originally.. since the pedal stays up it always reads the voltage which applies to 0% throttle when cruise is on.. that was my big issue and why i set out to get my J1939 link working correctly..

So are you saying if the throttle is at 0%, voltage will be low or at 0 and mess with the transmission shifting in a bad way while cruise is on?

Or are you saying if the throttle is at 0%, voltage remains high when cruise is on because cruise sends the higher voltage and the transmission works correctly?

[cadillackid]

I cant remember if the voltage is low or high when the throttle is 0% it doesnt matter..


the box they used whe ni got mine.. converts the TPS voltage from your pedal into J1939 data.. at the J1939 level throttle is sent across in a number that pertains to 0%-100% throttle.. 0% is pedal up meaning no foot.. 100% is pedal smashed to the floor..


for electronic engines without a J1939 data link their device has the ability to read the voltage from your pedal sensor (TPS) and convert it to J1939 that is then sent to the transmission in the form of 0%-100% depending on your pedal position...


when you run cruise control your foot pedal is always no foot or 0%.. so the throttle position number sent to the transmission is always 0% no matter what the engine demand is...



if you note when you drive a regular car or a properly operating modualted transmission bus.. the transmission shifts at a higher RPM the more you have your foot down.. in fact if you floor a car it will shift at somewhat close to the red line... a bus will do the same....



it will also downshift earlier.. ever notice if you go to pass someone or climb a steep hill in a car that as you press down the car downshifts to give you the power you need...



if you let off your pedal and coast to a stop notice your transmission stays in its higher gears for a fairly long time before finally downshifting to a lower gear.. this is normal for coast down...



now lets talk driving your bus with a pedal voltage sensor..lets say you drove at light throttle till it upshifted to 6th gear.. at light throttle you probably sit at 1400 RPM or so... if you mashed the pedal to the floor.. the transmission would drop instantly to 5 and likely to 4 so you could get up to the higher speed you desire....


you are driving along in 6th gear and you come upon a hill... you start slowing down as you begin.. so you step on the pedal a bit harder... a little harder yet and pop.. it drops to 5th gear.. the hill gets steeper you slow down a bit more.. so you mash it for the most power.. pop it goes down to 4 and now your turbo spools and you speed up.. as you speed up you let off a bit and it goes back to 5 and eventually to 6th as you crest the hill..


now drive along in 6th and you hit an exit ramp so you are foot off the pedal and you watch your RPMs go way down before it drops to 5.. you slow way down and it finally drops to 4 as you go round the ramp.. no foot on the pedal.. probably light brakes..


this is driving normally as im sure you have done hundreds it not thousands of times..


now imagine driving your bus where you hit resume on the cruise control.. and it stays in 6 as if you were coasting... you are going up the hill and slowing down more and more as the engine lugs.. you *FINALLY* get a downshift from 6 to 5 at the same speed you got the downshift while coasting... why?? because the TCM thinks your foot is off the pedal (because it is).. it sees 0% throttle.. it has no idea that the engine is lugging itself to death on the other end... it has no idea the cruise is on.. all it knows is 0% throttle.. now if you suddenly mashed the pedal to the floor (wit hcruise still on)... it would downshift as the pedal sensor would be sending throttle data to the transmision that said "hello! im floored".. the TCM would drop gears... but as soon as you left your foot off it would upshift right away again and youd be laboring once again...


see what im saying? it isnt measuring engine load or requested throttle, etc.. its only measuring what your physical foot is doing....






whe i enable cruise on mine.. (fully integrated J1939). my foot pedal stays at 0% like yours does.. however the Engine ECM sends through several other parameters.. the ECM sends the fact cruise is enabled, ad the setpoint to the TCM.. it sends through the engine load factor .. this is a number 0% - 100% based on the perceived power requested by the ECM ffrom the engine... when in cruise mode the allison TCM reads this engine load factor and applies it to the throttle parameter.. so it knows that the engine power is increasing and that its laboring so it can issue a downshift.... another parameter sent is called a "kickdown request".. this parameter comes from the Engine ECM over the J1939 and essentially tells the allison.. "please drop a gear and do it now".. its an override of sorts.. when this request comes across the allison will drop down a gear no matter what.. unless it would cause an over-rev of the engine.. on the other end the transmission is sending its gear data back to the ECM.. so the ECM knows that the transmission has performed the requested operation....



im not sure how to explain it any simpler... I no longer have the wiring installed in my bus to connect my CAC box as it once was to demo it for you.. once i figured out my engine had J1939 I quit using it..

[nikitis]

Originally Posted by cadillackid

I cant remember if the voltage is low or high when the throttle is 0% it doesnt matter..


the box they used whe ni got mine.. converts the TPS voltage from your pedal into J1939 data.. at the J1939 level throttle is sent across in a number that pertains to 0%-100% throttle.. 0% is pedal up meaning no foot.. 100% is pedal smashed to the floor..


for electronic engines without a J1939 data link their device has the ability to read the voltage from your pedal sensor (TPS) and convert it to J1939 that is then sent to the transmission in the form of 0%-100% depending on your pedal position...


when you run cruise control your foot pedal is always no foot or 0%.. so the throttle position number sent to the transmission is always 0% no matter what the engine demand is...



if you note when you drive a regular car or a properly operating modualted transmission bus.. the transmission shifts at a higher RPM the more you have your foot down.. in fact if you floor a car it will shift at somewhat close to the red line... a bus will do the same....



it will also downshift earlier.. ever notice if you go to pass someone or climb a steep hill in a car that as you press down the car downshifts to give you the power you need...



if you let off your pedal and coast to a stop notice your transmission stays in its higher gears for a fairly long time before finally downshifting to a lower gear.. this is normal for coast down...



now lets talk driving your bus with a pedal voltage sensor..lets say you drove at light throttle till it upshifted to 6th gear.. at light throttle you probably sit at 1400 RPM or so... if you mashed the pedal to the floor.. the transmission would drop instantly to 5 and likely to 4 so you could get up to the higher speed you desire....


you are driving along in 6th gear and you come upon a hill... you start slowing down as you begin.. so you step on the pedal a bit harder... a little harder yet and pop.. it drops to 5th gear.. the hill gets steeper you slow down a bit more.. so you mash it for the most power.. pop it goes down to 4 and now your turbo spools and you speed up.. as you speed up you let off a bit and it goes back to 5 and eventually to 6th as you crest the hill..


now drive along in 6th and you hit an exit ramp so you are foot off the pedal and you watch your RPMs go way down before it drops to 5.. you slow way down and it finally drops to 4 as you go round the ramp.. no foot on the pedal.. probably light brakes..


this is driving normally as im sure you have done hundreds it not thousands of times..


now imagine driving your bus where you hit resume on the cruise control.. and it stays in 6 as if you were coasting... you are going up the hill and slowing down more and more as the engine lugs.. you *FINALLY* get a downshift from 6 to 5 at the same speed you got the downshift while coasting... why?? because the TCM thinks your foot is off the pedal (because it is).. it sees 0% throttle.. it has no idea that the engine is lugging itself to death on the other end... it has no idea the cruise is on.. all it knows is 0% throttle.. now if you suddenly mashed the pedal to the floor (wit hcruise still on)... it would downshift as the pedal sensor would be sending throttle data to the transmision that said "hello! im floored".. the TCM would drop gears... but as soon as you left your foot off it would upshift right away again and youd be laboring once again...


see what im saying? it isnt measuring engine load or requested throttle, etc.. its only measuring what your physical foot is doing....






whe i enable cruise on mine.. (fully integrated J1939). my foot pedal stays at 0% like yours does.. however the Engine ECM sends through several other parameters.. the ECM sends the fact cruise is enabled, ad the setpoint to the TCM.. it sends through the engine load factor .. this is a number 0% - 100% based on the perceived power requested by the ECM ffrom the engine... when in cruise mode the allison TCM reads this engine load factor and applies it to the throttle parameter.. so it knows that the engine power is increasing and that its laboring so it can issue a downshift.... another parameter sent is called a "kickdown request".. this parameter comes from the Engine ECM over the J1939 and essentially tells the allison.. "please drop a gear and do it now".. its an override of sorts.. when this request comes across the allison will drop down a gear no matter what.. unless it would cause an over-rev of the engine.. on the other end the transmission is sending its gear data back to the ECM.. so the ECM knows that the transmission has performed the requested operation....



im not sure how to explain it any simpler... I no longer have the wiring installed in my bus to connect my CAC box as it once was to demo it for you.. once i figured out my engine had J1939 I quit using it..

Ok, what you just said makes perfect sense. So in effect Cruise will still work somewhat once I'm up to speed and assuming I don't go up any steep hills, but it can cause lugging of the engine when I do because the throttle is at 0% with no way to read Engine load with CAC's solution and it won't downshift to give me more power. So Cruise works, as CAC would say, but what they are not saying is just not as well on hills due to the reasons you stated above because it won't downshift when you need more power due to throttle at 0.

With that setup, I'm not terribly dismayed by that if it will work for long straight drives. I can always tap the brake to end cruise when I go up a steep hill or begin lugging, to make it down shift, or is it more of a problem than I'm perceiving?

So you are also saying it would be better to have CAC use my AU device during install so it can have the J1708 RPM and Throttle data sent to the Transmission TCM for perfect cruise control functionality.

Scratch that. CAC quoted me $19,000. And with a cruise that only partially works. That ain't happening. Guess I'm doing this myself.

[nikitis]

Ok, so CAC noted a lot of things extra which I didn't think I needed. Here are the items listed.

Maybe you guys can clarify what I require.

Allison & TC Core, $1400 (Reasonable)

Custom Tripple Clutch Converter $1800 (A little high IMO)

Reman Allison SAE3 Bell Housing & industrial 2 wheel drive $5400 (Does the bell housing not come with the Core? And what is industrial 2 wheel drive?)

4th gen 2400 TPS wire harness kit with TPS & Tap $3150 (Their customer TCM and harness, a bit high IMO)

2 Line LED Display $500 (Why do I need this?)

Throttle Position Sensor Kit $350 (Reasonable)

Lokar Shifter 16in Black $701 (Do they think my Bus is a Manual?)

Derale Thermostatic Bypass $80 (What is this for?)

Gallons TES 668 Synthetic Fluid $53 (Reasonable)

Installation Labor $5280 (billed as 32 hours but said that would go down if it was less and likely will be, even at $15k, we're still way over priced for this job IMO.

Shop supplies $150 (Reasonable)


So that being said, if I go the ME route, I do not need all of that correct? What exact parts do I need as I'm ready to pull the trigger on purchasing.

[Omnibot2000]

Originally Posted by nikitis

Ok, so CAC noted a lot of things extra which I didn't think I needed. Here are the items listed.

Maybe you guys can clarify what I require.

Allison & TC Core, $1400 (Reasonable)

Custom Tripple Clutch Converter $1800 (A little high IMO)

Reman Allison SAE3 Bell Housing & industrial 2 wheel drive $5400 (Does the bell housing not come with the Core? And what is industrial 2 wheel drive?)

4th gen 2400 TPS wire harness kit with TPS & Tap $3150 (Their customer TCM and harness, a bit high IMO)

2 Line LED Display $500 (Why do I need this?)

Throttle Position Sensor Kit $350 (Reasonable)

Lokar Shifter 16in Black $701 (Do they think my Bus is a Manual?)

Derale Thermostatic Bypass $80 (What is this for?)

Gallons TES 668 Synthetic Fluid $53 (Reasonable)

Installation Labor $5280 (billed as 32 hours but said that would go down if it was less and likely will be, even at $15k, we're still way over priced for this job IMO.

Shop supplies $150 (Reasonable)


So that being said, if I go the ME route, I do not need all of that correct? What exact parts do I need as I'm ready to pull the trigger on purchasing.

Most 1000 series transmissions are found in the chevy trucks, then you can unbolt the housing and stick on an SAE3 to fit your engine.

OR

Just buy a 2000 series with the SAE housing? Why does it have to be a 1000 series? They are essentially the same transmission, generally just have to look for the wide ratios and narrow ratio. The rebuild manual from Allison is the same manual covering both series.

As for the torque convertor. I have not purchased many torque convertors but the last one I purchased for my ford was rebuilt with stock stall speed, triple disc lock up with billet front cover for $500 Canadian. I would phone around local trans. shops. If your convertor is good, you can have it rebuilt local.

$15000 or $19000 for this transmission.....I would be purchasing a whole entire bus for $2000 that is one box with a 2000 series and would convert the whole thing electrically with the Allison. You might think I am crazy about it but I have converted automatic cars to standards including wire harnesses. Swapping over a wire harness is really not that difficult. If you need to swap injectors too, then swap injectors. Or keep them and purchase Orion and flash it to run single shots.

I would research it.