T444E w/ AT2000 vs. Cummins 24v Comparison, Economy, Durability

rw3iss · 10-19-2016, 02:59 PM

Hiyas,

I'm looking at a couple of buses and trying to find an engine that will get the best fuel economy and also last me more than 250k miles or so.

The first bus is a 2000 International with the T444E and a *manual* Allison AT2000 transmission

The second bus is a 2000 Flatnose Bluebird with a Cummins 24v engine (not sure of the transmission at the moment).

Both are mini-buses (not full size), and diesel (if that's not obvious).

I also see a lot of deals for Ford E450 buses (I think with the 7.3L diesel engine), if that is at all a competitor...

Would either of these definitely be preferable for fuel economy? I'm assuming the manual would get me a little more. Also, would either be more durable and longer lasting than the other? I've heard good things about both. Some say the Cummins can get 15-20mpg. Any truth to this in a school bus?

Thanks for any help!!

Geo Jeff · 10-19-2016, 03:14 PM

My power stroke with a automatic in it pulling me 19ft boat always gets me 20 mpg. A buddy tells me in his dodge truck with a 24 valve he gets smidgen better. I'm not sure i want to drive a stick around since the get the same MPG now if there the same ratio. but if that stick has taller gear than the auto it may very well be a super MPG but i would still not want to drive a stick on my bus. I love me some power stroke! But that cummins is so much easier to service in my opinion. I don't think you can go wrong here. do you want to drive a stick or auto.

Tango · 10-19-2016, 03:22 PM

You will find fans of both those engines...it's kind of a "Ford v Chevy" thing here. But, the Allison 2000 series are all automatic transmissions. They may be referring to the shifter mechanism. There are a few out there with mechanical shifters (I just installed such on my 2200MH). Also be aware there are a number of different models within the 2000 designation. If you can find out exactly which one it is, you can look the specs up on the Allison website.

Hard to compare when we don't know what the other tranny is. If an older AT545, then I'd go with the unit with the 2000 in it. It will have 5 speeds vs four in a 545 and a sixth gear can often be unlocked. It will also feature "lock up" which will save a lot of fuel as well as brakes in hilly country.

Good luck with them and let us know what you discover.

rw3iss · 10-19-2016, 03:27 PM

Thanks, I'll get back with more info on the other transmission.

Regarding the 2000, I've asked for more info, but can you possibly tell me what you mean by a 'manual shifter'? Does this mean I still shift going up/down hills and changing speeds? Or when is it employed? Does the automatic transmission + manual shifter still benefit from other manual transmission characteristics such as higher fuel economy?

Geo Jeff · 10-19-2016, 03:27 PM

Quote:

Originally Posted by Tango

You will find fans of both those engines...it's kind of a "Ford v Chevy" thing here. But, the Allison 2000 series are all automatic transmissions. They may be referring to the shifter mechanism. There are a few out there with mechanical shifters (I just installed such on my 2200MH). Also be aware there are a number of different models within the 2000 designation. If you can find out exactly which one it is, you can look the specs up on the Allison website.

Hard to compare when we don't know what the other tranny is. If an older AT545, then I'd go with the unit with the 2000 in it. It will have 5 speeds vs four in a 545 and a sixth gear can often be unlocked. It will also feature "lock up" which will save a lot of fuel as well as brakes in hilly country.

Good luck with them and let us know what you discover.

good call bus geek, get a 6 speed if you can. our motor home has it with a c7 cat and its a amazing transmission.

Tango · 10-19-2016, 03:45 PM

Most Allison installations feature an electronically controlled shifter...either with a T-handle or push buttons. But there is also an all mechanical (cable) shifter available for just about any Allie. The shifters are NOT made or speced by Allison. That is the call of the chassis manufacturer so there are any number of possible variations. With a mechanical, you can indeed select gears manually. But most folks just stick it in DRIVE and let the tranny itself pick the gears.

rw3iss · 10-19-2016, 03:58 PM

Quote:

Originally Posted by Tango

Most Allison installations feature an electronically controlled shifter...either with a T-handle or push buttons. But there is also an all mechanical (cable) shifter available for just about any Allie. The shifters are NOT made or speced by Allison. That is the call of the chassis manufacturer so there are any number of possible variations. With a mechanical, you can indeed select gears manually. But most folks just stick it in DRIVE and let the tranny itself pick the gears.

Ah, interesting, thanks

Apparently the bus doesn't necessarily have an Allison 2000, but rather a "standard transmission". He can't find a specific model on it, so I'll probably just forego it for now. Will let you know if i find more out.

rw3iss · 10-19-2016, 04:11 PM

Well the guy isn't sure what kind of transmission is in the Cummins 24v, some kind of Allison... He was saying that possibly the year 2000 buses only came with the AT545. Anyone know if this is true? Here's the bus:
http://philadelphia.craigslist.org/cto/5781654070.html

He also says he has some 2003 International DT466 6-cylinder's coming in with 150k miles, 65 passenger, Allison transmission (not sure of model yet), air brakes and hydraulics, for $3500. Sounds like a good deal, I think!

rw3iss · 10-19-2016, 04:46 PM

I'm curious if anyone knows of the typical MPG of the Cummins 24v buses with an Allison 545 or Allison 2000 transmission? I've heard some superior things like ~20mpg highway, just wondering if that's true.

mikeypj · 10-23-2016, 01:55 PM

So in a perfect world, what is the ideal engine tranny combo? Airbrakes vs hydraulic brakes?

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cowlitzcoach · 10-23-2016, 05:22 PM

There is no ideal engine and transmission power package. Some are better than others for particular applications while others are better for other applications.

Many of the school districts here in WA state are not going for the big engines in the big buses any longer. On routes they do not get warm enough to get the emissions systems working properly. The little engines that have to work really hard are doing much better for them.

I might be mistaken but I would bet that every bus built in model year 2000 with an Allison had some variation of the Allison 1000/2000/3000 transmission. The engines would have been fully electronic and they work better with a fully electronically controlled transmission. Some still had a manual control for gear selection instead of push buttons. But the operation of the transmission itself was fully electronic.

I would say the odds of it having a manual stick shift are about a million to one. I am not saying it couldn't have one but the likelihood of it being a manual stick shift is right up next to winning a lotto.

As far as which bus would work for you better, only you can make that determination. The T444E is a great engine and easily goes well in excess of 300K miles in a school bus. The Cummins 24V ISB is also a great engine that has been known to go lots and lots of miles. Both will get similar fuel mileage but on average it takes less fuel to fill up six holes than eight holes.

As far as actual fuel mileage numbers, anyone who told you they were getting 20 MPG in their bus I want to meet them to see what they were doing to get such fantastic fuel mileage numbers. I have seen some fleet averages that were 3%-5% higher from one district to another but I have never seen a bus that got 2x some of the highest fuel mileage averages I have ever seen. Realistic numbers are going to be in the 8-14 MPG range. It all depends upon how fast you go, how many barnacles are on the roof, how high the roof is, and how hard the wind was blowing for or against you. I have driven into the wind that was blowing so hard I couldn't get into high gear. And on the way home the tail wind meant I barely had to touch the throttle to keep my speed up.

Both of the buses you indicated would be head and shoulders above a Ford E-350 chassis bus simply because the Ford E-350 has very little weight carrying capacity left--a bus that weighs over 9,000 lbs. with a 12,000 GVWR can not carry nearly as much as a bus that weighs 12,000 lbs. and has a 19,000 lbs. GVWR.

If you decide neither of the first two buses work for you I would say to look seriously at any of the DT466 buses with air brakes. Air brakes are much better suited to vehicles that sit a lot. Moisture from sitting around kills hydraulic brakes fairly quickly. Additionally, most air brake equipped buses have more braking surface. I am a firm believer in you can never have too much braking surface.

Good luck and happy trails to you!

mikeypj · 10-23-2016, 05:42 PM

Im looking for an engine that will go high miles, a tranny that i can roll along at 65-70 mph. I know nothing about airbrakes so if they go kaput i cant fix them. Right now im compiling my list for the wants for my bus.

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cadillackid · 10-23-2016, 06:39 PM

my 2000 T-444E has a partially electronic AT545 in it... ive seen them in some 01's as well...

the modulator is electronic instead of a cable... and it is not handled by the PCM but a simple TPS via the accelerator pedal sent directly to the transmission...

the PCM on my bus has the ports to run a 1000/2000 series trans.. and the computer program has the option to set it..

I should add that in a short bus like my 6 window bluebird.. the 190 HP T-444E and AT545 is fantastic.. I replaced my fuel pressure regulator per a TSB to the later model part.. the bus has lots of power (for a school bus) and even without lockup the 545 doesnt work hard.. that bus will run 65 all day and runs the T-444E right around its peak power output RPM of 2300...

in a bigger full size bus id feel like the 444E would be under powered and probably have to work hard to keep up... though like cowlitz mentioned you want your engine to warm up.. though a LOT of people I talk to find their 444E's run too hot im the summer mainly because of the IHC 1/2 rad 1/2 turbo setup...

im not sure why the DT's dont seem to have the issue of running warm... perhaps just because of the much more iron mass in the block distributes heat better? or maybe the engines are running at less than full power output so not generating as much heat? hard to tell.. but i dont hear many people talking about DT-466(e) running hot.. but I do with T-444E's...

driving around town in cooler weather (even a mildly cool 38 this morning in ohio) it took a good lomg time for my bus to warm up to 190... and I only had 2 heaters turned on low fan... im guessing if I were running stop N go traffic in 10 degree weather with all the heaters on that bus would never warm up..

-Christopher

prof.fate · 10-28-2016, 11:43 AM

airbrakes are pretty simple - you have an air compressor on the engine, a governor (to turn it on/off as pressure rises/drops), a tank (or 2) and gauges, then front and rear actuators, the rear containing the spring brake.
AFAIK, all are drum with S cams.

Air had moisture in it (humidity!) and when compressed you get water in the tanks. You want/need to get this water out for many reasons - in winter it can freeze and make the brakes inoperable, it can cause rust in the system.

tanks are split into multiple parts to separate the water (wet and dry sides to the tanks). On old systems you'd have to drain the moisture (home air compressors need this done). Some newer buses (all the ones at my employer) include filters and automatically spit the water out. I think a filter is good for 100k miles, but it depends on many factors like the humidity where you are.

Once you have air on board you can do other things with it - so it's not all bad.

EastCoastCB · 10-28-2016, 12:15 PM

Quote:

Originally Posted by rw3iss

I'm curious if anyone knows of the typical MPG of the Cummins 24v buses with an Allison 545 or Allison 2000 transmission? I've heard some superior things like ~20mpg highway, just wondering if that's true.

No that is absolutely not going to happen. MAYBE 12 on a good day in perfect conditions. MAYBE.

EastCoastCB · 10-28-2016, 12:18 PM

Quote:

Originally Posted by mikeypj

Im looking for an engine that will go high miles, a tranny that i can roll along at 65-70 mph. I know nothing about airbrakes so if they go kaput i cant fix them. Right now im compiling my list for the wants for my bus.

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Get a Cummins 8.3 or International DT466 with at least a 643 tranny but shoot for a 2000 or 3060 so you get an overdrive. Find one with a driveline retarder for the ultimate school bus combo for interstate trucking and mountain passes.
OR- find a Gillig school bus with a big Detroit two stroke. Or a crown if you have really deep pockets and really great luck/timing.

mikeypj · 10-28-2016, 12:32 PM

Quote:

Originally Posted by EastCoastCB

Get a Cummins 8.3 or International DT466 with at least a 643 tranny but shoot for a 2000 or 3060 so you get an overdrive. Find one with a driveline retarder for the ultimate school bus combo for interstate trucking and mountain passes.
OR- find a Gillig school bus with a big Detroit two stroke. Or a crown if you have really deep pockets and really great luck/timing.

Im going to look for one with an OD, but with the OD will ihave to shut it off if i have a toad?

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