Looking for opinions on axle or trans swap.

[cadillackid]

Because it's what they have. It's what a large number of buses had installed. And most don't know the flaws of one like you, I, and a number of others here do. It's honestly one of the few things that irks me when a seller asks 100k for a conversion that has an at545, as I'd bet big money a trans failure is in the buyer's future.

If the 545 had used value, I'd say pull it while it's good and sell it. But they don't, so grenade the f'er and then swap it to a better transmission. Heck, I can't even sell a used mt643 for 500 bucks, what's that make an at545 worth?

I think the navistar dump in 2018 satisfied the 643 appetite.. for 500 bucks or close to it i got a fresh dry reman 643 with converter... the place had a warehouse full of em.. it was navistar dumping their inventory after the mandated 15 year hold past EOL date... you figure the last 643 went out the door in a truck / bus 21 years ago so the market is smaller now.. im surprised skoolies are still managing to find busses with 545's in them as most everything on the auctions these days is 02+ with 2000/3000 series but apparently the cheap busses are the ones they find which are the older ones with 545's. to me it would be prudent to spend a couple grand more and buy a bus with a 2K. , but like you say maybe they havent researched it ahead of time and have no idea.. and just read the word "allison" and assume its a great quality transmission.



and maybe the idea if you have a 545 is to toss a spare under the queen size bed in the back of the bus... swapping a 545 out for another really is pretty straight forward in a bus..

 

[Booyah45828]

It'd be less computer work to swap an mt643 then a 2000. Dt360 wasn't used by the time the 2000 rolled around, so you'd have to customize a swap. Not impossible, but I wouldn't consider it an easy task as you wouldn't be able to use a donor like most have for their 2000 swaps.

 

[Booyah45828]

I think the navistar dump in 2018 satisfied the 643 appetite.. for 500 bucks or close to it i got a fresh dry reman 643 with converter... the place had a warehouse full of em.. it was navistar dumping their inventory after the mandated 15 year hold past EOL date... you figure the last 643 went out the door in a truck / bus 21 years ago so the market is smaller now.. im surprised skoolies are still managing to find busses with 545's in them as most everything on the auctions these days is 02+ with 2000/3000 series but apparently the cheap busses are the ones they find which are the older ones with 545's. to me it would be prudent to spend a couple grand more and buy a bus with a 2K. , but like you say maybe they havent researched it ahead of time and have no idea.. and just read the word "allison" and assume its a great quality transmission.



and maybe the idea if you have a 545 is to toss a spare under the queen size bed in the back of the bus... swapping a 545 out for another really is pretty straight forward in a bus..

All good points. Most of the time it's easier and costs ahead to buy good then to build good. I looked for those remans again and couldn't find them, only found used units for $1000+, but lkq did change their website so I imagine they still have them around somewhere.

When I was actively using my bus, I had a spare engine and trans in the shop ready to go. Not because what I had was junk and ready to fail, but because I knew if anything did ever fail, finding a replacement was half the battle.

 

[dbsoundman]

All good points. Most of the time it's easier and costs ahead to buy good then to build good. I looked for those remans again and couldn't find them, only found used units for $1000+, but lkq did change their website so I imagine they still have them around somewhere.

When I was actively using my bus, I had a spare engine and trans in the shop ready to go. Not because what I had was junk and ready to fail, but because I knew if anything did ever fail, finding a replacement was half the battle.

I have to say, if I didn’t already have a bus I would likely buy yours, I’ve got it saved on marketplace just so I can check it out.

 

[cadillackid]

yeah!! getting a spare when its available vs when you need it is a Huge advantage.. you look for someone dumoing something or notice it and buy it up.. definitely a much better way to go buying parts on your terms vs being busted and needing something right away.. esp something like a spare IDI engine that isnt real common anymore..

 

[nikitis]

Since we're on the subject. Could I use a MT643 on my T444E with that converter ring? 1995 3box?

I checked the gearing for MT643, and it looks decent. I just never considered that option before because I thought the M in MT meant manual transmission, but apparently I learned they are automatic.

 

[dbsoundman]

Since we're on the subject. Could I use a MT643 on my T444E with that converter ring? 1995 3box?

I checked the gearing for MT643, and it looks decent. I just never considered that option before because I thought the M in MT meant manual transmission, but apparently I learned they are automatic.

Don’t worry, I assumed M was for manual as well, I learned later that it was in fact an automatic.

Others that are more experts in this area will for sure chime in but I do believe Booyah has an MT643 for sale if you can figure out how to get it from his place to yours.

 

[Booyah45828]

I have to say, if I didn’t already have a bus I would likely buy yours, I’ve got it saved on marketplace just so I can check it out.

Thanks buddy. I've had people checking it out weekly since posting it last year. Not sure which one you have saved, but once interest starts to wane I repost another listing and get hounded by people again, I don't understand FB marketplace's algorithm, but interest seems to die off substantially anywhere from 2 weeks to a month later.

M is the series. Allison most commonly had at, mt and ht series transmissions and those are the order from least torque capacity to highest torque capacity. AT is smallest and lightest duty, which makes it the cheapest to buy, which is why it's so popular in school buses.

I've got an MT643 for sale. I bought it used off a dt466. My original plan was to rebuild it and iron out the mounting details to my idi, and then have it as a backup in case my at545 failed. Then lkq started selling the remans that were cheaper then a master rebuild kit, and I looked into buying one and having it shipped via freight, then c19 happened and freight shippers went gonzo and put that plan on hold.

If you have a t444e, follow CK's lead and go with a 2k series. Much easier and common to find, and you've already gotten an electronic engine, so you're saving nothing by going with an old/outdated mechanical trans. The world series transmissions (1k,2k,3k,4k series transmissions) are light years ahead of the old units as far as reliability is concerned, and you get an OD gear or two on top of it.

 

[nikitis]

Thanks buddy. I've had people checking it out weekly since posting it last year. Not sure which one you have saved, but once interest starts to wane I repost another listing and get hounded by people again, I don't understand FB marketplace's algorithm, but interest seems to die off substantially anywhere from 2 weeks to a month later.

M is the series. Allison most commonly had at, mt and ht series transmissions and those are the order from least torque capacity to highest torque capacity. AT is smallest and lightest duty, which makes it the cheapest to buy, which is why it's so popular in school buses.

I've got an MT643 for sale. I bought it used off a dt466. My original plan was to rebuild it and iron out the mounting details to my idi, and then have it as a backup in case my at545 failed. Then lkq started selling the remans that were cheaper then a master rebuild kit, and I looked into buying one and having it shipped via freight, then c19 happened and freight shippers went gonzo and put that plan on hold.

If you have a t444e, follow CK's lead and go with a 2k series. Much easier and common to find, and you've already gotten an electronic engine, so you're saving nothing by going with an old/outdated mechanical trans. The world series transmissions (1k,2k,3k,4k series transmissions) are light years ahead of the old units as far as reliability is concerned, and you get an OD gear or two on top of it.

I have an older T444E from 94/95 using J1708. Are any of the 1k-4k trans straight swaps or do I need converter rings, and a converter electronic device to make it work with J1939 transmissions? I'd prefer a straight swap drop in as that would be easier for me to do on my own, unless there are guides on how to add any necessary ring adapters / electronic converters.

 

[cadillackid]

I have an older T444E from 94/95 using J1708. Are any of the 1k-4k trans straight swaps or do I need converter rings, and a converter electronic device to make it work with J1939 transmissions? I'd prefer a straight swap drop in as that would be easier for me to do on my own, unless there are guides on how to add any necessary ring adapters / electronic converters.

on your 3 Box T444E there is no J1939 data link.. (that came out with the single box).. in the original scheme.. allison used WTEC-II (J170 to run their first gen "world" series (essentially a 3000) transmissions...



to use an allison 1000 or 2000.. the boltup itself is easy.. unbolt the 545 and bolt up the 1k/2k. (this assumes you buy an SAE3 transmission.. Most of the 2k in school busses are SAE3.



if you have air brakes like is easy.. no parking brake to deal with.. hydraulic brakes then you will want to try and find an A2000 that already has the parking brake assembly on the back of it, otherwise you''ll have to source one and its bracket...



your old shifter will work.. I had to mod the bracket slightly but not a big deal really..



you'll need to have the driveshaft shortened (good time to get the set balanced since it will likely be spinning faster as you drive at higher speeds).



the one thing I do not know is how a 3 box handles the speed sensor being a signal from a transmission and not a physical sensor.. i had to change the transmission type in my single box.. im guessing the 3 box has the same? just something ive not dealt with..



CAC makes a electronic to J1939 throttle conversion so you can use it with a standard J1939 TCM that was used on most. it works pretty well (I have one laying in the garage).. it measures your pedal signal and transmits it to the transmission... the only thing it doesnt work with is cruise control.. since the cruise control on a T444E doesnt move the physicasl pedal.. the transmission never wanted to downshift on hills.. (thus why I went a different direction)...



the ultimate swap was the one rolesvillemariana did here a couple years ago where he bought a donor bus and swapped everything ever from that bus.. transmission, harness , brackets, etc.. and then even swapped his old 545 into the donor and sold it as a runner driver with a 545... that was epic!

 

[nikitis]

on your 3 Box T444E there is no J1939 data link.. (that came out with the single box).. in the original scheme.. allison used WTEC-II (J170 to run their first gen "world" series (essentially a 3000) transmissions...



to use an allison 1000 or 2000.. the boltup itself is easy.. unbolt the 545 and bolt up the 1k/2k. (this assumes you buy an SAE3 transmission.. Most of the 2k in school busses are SAE3.



if you have air brakes like is easy.. no parking brake to deal with.. hydraulic brakes then you will want to try and find an A2000 that already has the parking brake assembly on the back of it, otherwise you''ll have to source one and its bracket...



your old shifter will work.. I had to mod the bracket slightly but not a big deal really..



you'll need to have the driveshaft shortened (good time to get the set balanced since it will likely be spinning faster as you drive at higher speeds).



the one thing I do not know is how a 3 box handles the speed sensor being a signal from a transmission and not a physical sensor.. i had to change the transmission type in my single box.. im guessing the 3 box has the same? just something ive not dealt with..



CAC makes a electronic to J1939 throttle conversion so you can use it with a standard J1939 TCM that was used on most. it works pretty well (I have one laying in the garage).. it measures your pedal signal and transmits it to the transmission... the only thing it doesnt work with is cruise control.. since the cruise control on a T444E doesnt move the physicasl pedal.. the transmission never wanted to downshift on hills.. (thus why I went a different direction)...



the ultimate swap was the one rolesvillemariana did here a couple years ago where he bought a donor bus and swapped everything ever from that bus.. transmission, harness , brackets, etc.. and then even swapped his old 545 into the donor and sold it as a runner driver with a 545... that was epic!

Ok, lots of questions still.

So my Bus is likely an SAE3 mount type according to you.

I know my bus has J1708. This is why I'm asking if I need an electronic converter for a transmission that requires J1939. The converter would translate my J1708 ECM to the J1939 Transmission. Is this thing plug and play from CAC? That would be simple enough if that's all I had to do.

I do have cruise control, so if I upgrade I guess I have to kiss that good bye then but I think I'd rather have speed and reliability, so I can deal with that if there's no way to re-add cruise control.

As for the speed sensor. My current one is mechanical where the transmission spins a magneto, and it oscillates the frequency. Would an A2000 SAE3 with a Converter require something extra for the speed sensor or is mine plug and play? Or do they make a A2000 speed sensor that works similarly? I don't know if the A2000 can make use of this or if it has it's own electronic speed sensor using data values and if it's compatible with my ECM or not.

 

[cadillackid]

Ok, lots of questions still.

So my Bus is likely an SAE3 mount type according to you.

I know my bus has J1708. This is why I'm asking if I need an electronic converter for a transmission that requires J1939. The converter would translate my J1708 ECM to the J1939 Transmission. Is this thing plug and play from CAC? That would be simple enough if that's all I had to do.

I do have cruise control, so if I upgrade I guess I have to kiss that good bye then but I think I'd rather have speed and reliability, so I can deal with that if there's no way to re-add cruise control.

As for the speed sensor. My current one is mechanical where the transmission spins a magneto, and it oscillates the frequency. Would an A2000 SAE3 with a Converter require something extra for the speed sensor or is mine plug and play? Or do they make a A2000 speed sensor that works similarly? I don't know if the A2000 can make use of this or if it has it's own electronic speed sensor using data values and if it's compatible with my ECM or not.

so its not a J1708 to J1939converter (although I have built one of those i use in my own stuff).. you piggyback wires t othe throttle pedal harness and ths box converter the 0-5VDC signals it sees into J1939 TPS positional data.. (essentially 0-100 literaaly for %).



there really is no such thing as plug N play in the swap world.. its all a good bit of trial and error.. (as the dozens of pages in my 'Redbyrd transformation' would show)..



on my AT545 ther speed sensor was essentially 2 wires coming out of the back pf the transmission.. its a hall effect sensor which reads a tone ring thats on the tailshaft... im guessing the same as what you call spinning a magneto..



on the A2000 the speed signal is a single wire (from the TCM)(the A2000 doesnt send a user-connectble physical speed signal).


that has an AC low voltage signal which is output... the Navistar ECM is capable of reading such a signal.. but the programming in the computer needs to be changed from 'Allison AT/MT' (where it looks for a 2 wire signal) to 'Allison MD' (where it looks for a single wire signal)...



cruise control - you can use it on flat ground... the issue I had is that since the physical gas pedal stays up (the oedal doesnt physically move like your old cars did).. that the transmission will not want to downshift on hills as it thinks you are just coasting along. you can of course physically mash the pedal and it will downshift like a champ...



it was enough of an annoyance to me that caused me to change my whole thinking on how I did my integration..

 

[wanderingturtl]

OP, since you don't know the future of the bus, and you don't want to put the investment of a trans swap, it seems your don't want to invest much into the bus. So, here are a couple other options for you to consider:
1. taller tires, if possible. This can give you a 5-10 reduction in RPMs at the same speed. But you speedometer will be wrong; easy to compensate for with a speedometer app on your phone and tape and a marker on the speedometer.

2. noise canceling headphones.

 

[cadillackid]

OP, since you don't know the future of the bus, and you don't want to put the investment of a trans swap, it seems your don't want to invest much into the bus. So, here are a couple other options for you to consider:
1. taller tires, if possible. This can give you a 5-10 reduction in RPMs at the same speed. But you speedometer will be wrong; easy to compensate for with a speedometer app on your phone and tape and a marker on the speedometer.

2. noise canceling headphones.

speedometer is easily fixed on an IH mechanical engine with dip switch setting changes.. on an electronic engine its an easy change with the free version of servicemaxx..


Noise cancelling headphones are illegal in most states when worn by a driver..

 

[wanderingturtl]

speedometer is easily fixed on an IH mechanical engine with dip switch setting changes.. on an electronic engine its an easy change with the free version of servicemaxx..

Noise cancelling headphones are illegal in most states when worn by a driver..

I did not know either of those things.. Good ****. thank you