| Author |
 Topic  |
|
|
Buskid
Top Member
USA
3368 Posts |
 Posted - 03/13/2003 : 8:04:57 PM
|
Hello all,
I have a couple questions/concerns that I'd like a mechanical viewpoint on.
1. What is the difference between the Allison AT-545 and Allison 2000 transmission? Is one better than the other?
2. What would be the best transmission to spec. with an International DT-466 for optimal performance?
I was out looking and test driving some different AmTran RE school buses today. One 1996 had the T444E with the AT-545, one 1999 had the T444E with the AT-545, and one 2001 had the T444E with the Allison 2000.
I'm not planning on purchasing one of the used vehicles I test drove today. Rather, when I hopefully get the bid for a contract at a local school district, I'm planning on purchasing a new IC RE-300. I already know that I want a DT-466, but what transmission would you suggest coupling it with?
Any input would be helpful. 
PS: If anyone is currently running any of these AmTran/International/IC RE units with the DT-466s, I'd be very interested in hearing how satisfied you are with them.
Crown Supercoach - The “Royalty” of Pupil Transportation |
|
|
Peter
Top Member
USA
1057 Posts |
Posted - 03/13/2003 : 9:29:00 PM
|
You probably know that the 545 is a "four speed" and the 2000 is a "five speed." That being said, a 2000 makes for a better road bus. Are you planning to do a lot of highway driving? If so, go with the 2000. You can set the top speed at a higher limit and run the bus at that speed without sacrificing fuel mileage. Also, the 2000's ratios seem to be closer together, allowing you to maintain more speed while climbing hills.
I don't know if I have all of the terminology right for automatics; I just try to describe how they work in terms of real transmissions.
Have you thought about going with a CE with the 466 and a 7 speed manual? That would be pretty sweet!
|
 |
|
|
peil
Active Member
USA
34 Posts |
Posted - 03/13/2003 : 10:06:00 PM
|
I'm not that familiar with the 2000 transmission, but I think that it and the 545 are maybe a little light for a DT466, especially if you want any horsepower or torque. My feelings are that you would be happier with the World Transmission, probably the MD 3060. I have the AT545 in a 1999 with a smaller ISB Cummins, and have had problems with rough shifting. I have 3 Worlds, two with 280 HP Cummins' and one with a 250 HP DT466E. All the transmissions have been great, but I prefer the Cummins over the DT466E, but that might largely be due to better service at Cummins. And I might as well say it, the two are in BBAARE's and the other is in an Amtran FE, all 84 passengers. My drivers will all tell you that they like the BBAARE's the best.
David Peil |
|
|
|
Buskid
Top Member
USA
3368 Posts |
Posted - 03/14/2003 : 05:09:59 AM
|
Hi Peter,
No, the thought of an IC CE with a DT-466 and a 7-speed manual transmission never crossed my mind! After driving a 10-speed Crown in California, I've been spoiled rotten by automatics.
Thanks for the information, though. I knew the AT-545 was a 4-speed, but I'm not very familiar with the Allison 2000.
----------------------------------------
Hi peil,
Thanks also for the information.
About the transmissions — I had a feeling that an AT-545 would be too small. I've noticed the AT-545s in the full-sized transit-style school buses around here don't seem to last very long. That's what concerned me about the used buses I drove yesterday. I don't want to buy something that's going to give me problems down the road (literally).
The IC dealer I'm working with is offering me a great deal if I order a brand new bus, so that's what I've decided to do if this owner/operator thing works out.
Oh, and if I was at your school district, I'd probably also prefer the Blue Bird All American over the AmTran FE. That's only because I like rear engine school buses, though.
Crown Supercoach - The “Royalty” of Pupil Transportation |
|
|
|
wagonmaster
Top Member
USA
2298 Posts |
Posted - 03/14/2003 : 05:28:28 AM
|
I don't think it's an issue, because the AT-545 isn't being produced anymore. Clearly the 2000 is an improvement. It's electronic and computer controlled with an overdrive for added fuel economy, so you really have the "good" stuff. No comparison in my view, buy the 2000, all else being equal.
If, however, the buses are similar in condition and the one with the AT-545 is less money, you'd be foolish not to consider it, at least.
Good luck with your choice, whichever it may be.
Joe
|
|
|
|
slane
Active Member
18 Posts |
Posted - 03/14/2003 : 05:56:31 AM
|
The 545 is older, and electronics were added. The 2000s were built "with" all the electronics.
|
|
|
|
Buskid
Top Member
USA
3368 Posts |
Posted - 03/14/2003 : 06:10:36 AM
|
So, compared to something like the MD-3060, is the Allison 2000 just as good of a choice if the bus is only going to be used on regular school routes and occasional field trips?
Crown Supercoach - The “Royalty” of Pupil Transportation |
|
|
|
peil
Active Member
USA
34 Posts |
Posted - 03/14/2003 : 12:20:23 PM
|
You might want to search the web for Allison Transmissions. They give you a spec sheet on what transmission for what application. I assume that if you are going to use a DT466E, you will be looking at probably in the neighborhood of 250HP, in the range of 600 to 800 foot pounds of torque. If you are getting a RE that is 84 passenger, you are looking at a GVW of 32 to 35 thousand. If I am reading things right, the 2000 is too small for that application. Remember, this is a school bus that does a lot of stop and go. To me it is not advisable to undersize thing. Others might have other ideas, so guys, let me know if I am wrong.
David Peil |
|
|
|
bbird66
Top Member
USA
881 Posts |
Posted - 03/14/2003 : 1:30:15 PM
|
I've been around the 2000's for a while and I think they are the cats meow, They "talk" to the engine and the shifting is the way it should be. The 545's were ok but they cannot handle a steady diet of high torque and thank god they are not made anymore.
|
|
|
|
Buskid
Top Member
USA
3368 Posts |
Posted - 03/14/2003 : 5:24:51 PM
|
Any opinions on the MT-643? I have one in a 1990 Thomas Saf-T-Liner ER, but that's coupled with a Caterpillar 3208.
I looked up the MD-3060 and MT-643 on Allison's website. Thanks for pointing that out to me, peil.
I guess what I'm trying to ask is what transmission is going to keep up with the bus best and what transmission will I get the best value out of.
Crown Supercoach - The “Royalty” of Pupil Transportation |
|
|
|
peil
Active Member
USA
34 Posts |
Posted - 03/14/2003 : 6:54:02 PM
|
I've got the 643 with the 3208 Cat, both the 5.9 and 8.3 Cummins, as well as the DT466. I basically have no complaints with any of them. I have had to have a couple rebuilt this year and the totals have been in the 3 to 4 thousand range with R@R included. You will be impressed with the World though. It shifts a lot smoother, and the extra gear is nice. I am not sure how much more expensive they are than the 643, and I have no idea how expensive they are to work on, but warranty should cover that for some time. The only problem I am aware of on the World is they seem to have a little problem with seepage on the rear seal, but they might have a fix for that by now.
David Peil |
|
|
|
B. Busguy33
Top Member
USA
3444 Posts |
Posted - 03/14/2003 : 9:25:50 PM
|
quote:
2. What would be the best transmission to spec. with an International DT-466 for optimal performance?
Hi Trina,
I don't have all the experience that most of the members here have with regard to transmissions, but I would think the Allison MD3060 would be a great transmission to be coupled with the International DT466 diesel engine. Depending on the flatness of the land and the driving environment you would be experiencing, I may even go as far as spec'ing a retarder of some sort for a bus like that.
I believe the Allison 2000 transmission is mainly suited to replace AT-545 transmission applications and the MD3060 is meant for more heavy-duty work (such as a Type-D RE bus).
quote:
About the transmissions — I had a feeling that an AT-545 would be too small. I've noticed the AT-545s in the full-sized transit-style school buses around here don't seem to last very long. That's what concerned me about the used buses I drove yesterday. I don't want to buy something that's going to give me problems down the road (literally).
You definitely want to steer clear of an AT-545 transmission in an RE bus. As I am sure I have already told you, a large contractor ran many AmTran REs ('98-'00) in one of the districts close-by to my area with the T444E engine and AT-545 transmission. That company experienced many, many complete transmission failures.
I know of one bus in particular that was a 1999 AmTran RE that had the 444E and the AT-545 transmission failed a week before school the school year ended in 2002. That bus had about 65,000 miles on it at the time. Obviously, the AT-545 is not suited for the work of an MD3060 series (or maybe a 2000 series) transmission!
Good luck with your decision!
|
|
|
|
rswboe
Top Member
USA
675 Posts |
Posted - 03/17/2003 : 10:15:37 AM
|
Forget the 545, the're boat anchors. A completely disposable trans. The A2000 is the electronic generation and designed to be mated to an electronic engine. If yo ugo with the DT466E, go with the MD3060, it is a much heavier trans and will hold up very well.
|
|
|
|
Buskid
Top Member
USA
3368 Posts |
Posted - 03/17/2003 : 11:37:59 AM
|
Hey Bob,
Now that I think of it, I remember you mentioning the transmission failures to me before. Didn't that happen on Betty's bus?
----------------------------------------
Thanks rswboe,
I have pretty much decided on the DT-466 and Allison MD-3060 combination. If I do end up buying a used bus instead of a brand new one, it'll definitely not have the AT-545 in it. You all have just confirmed my negative feelings towards those transmissions. 
Crown Supercoach - The “Royalty” of Pupil Transportation |
|
|
|
Brad Barker
Administrator
USA
874 Posts |
Posted - 03/17/2003 : 2:32:41 PM
|
When a bus is specified when new it is coupled to an engine that produces a torque value that the transmission is rated for. I believe the AT-545 was designed to handle less than 550 lb. ft. of torque. If you couple it to an engine that produces, say, 525 to 550 lb. ft of torque it will be getting a work out most of its life and its life will be shortened. I believe you should specify a transmission that has a higher torque value than the maximum produced by the engine. I also, believe that the reason so many people have had problems with the AT-545 is that it borders on the maximum torque line produced by some engines. In order to save a few bucks on the initial cost of a bus, dealers sell and districts accept this action. This is my personal opinion. I have always felt that spending a few dollars more in the initial purchase will save you hundreds down the road. If you are retrofitting an older bus with a different transmission you need to pay close attention to the rated torque specifications of engine and transmission, matching for the appropriate combination.
Brad
|
|
|
|
Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 03/17/2003 : 4:38:37 PM
|
quote:
When a bus is specified when new it is coupled to an engine that produces a torque value that the transmission is rated for. I believe the AT-545 was designed to handle less than 550 lb. ft. of torque. If you couple it to an engine that produces, say, 525 to 550 lb. ft of torque it will be getting a work out most of its life and its life will be shortened. I believe you should specify a transmission that has a higher torque value than the maximum produced by the engine. I also, believe that the reason so many people have had problems with the AT-545 is that it borders on the maximum torque line produced by some engines. In order to save a few bucks on the initial cost of a bus, dealers sell and districts accept this action. This is my personal opinion. I have always felt that spending a few dollars more in the initial purchase will save you hundreds down the road. If you are retrofitting an older bus with a different transmission you need to pay close attention to the rated torque specifications of engine and transmission, matching for the appropriate combination.
Brad
Would 8.2L Detroits have less torque? I hear so many bad things about AT545s, but my bus has never has any transmission problems (or so I'm told).
Stop at: http://buses.thesummit.biz
This is an industry where people brag about their times for 60-0, not 0-60. |
|
|
|
B. Busguy33
Top Member
USA
3444 Posts |
Posted - 03/17/2003 : 5:04:42 PM
|
quote:
Now that I think of it, I remember you mentioning the transmission failures to me before. Didn't that happen on Betty's bus?
Yup. You are correct, Trina. I knew I had mentioned something to you awhile ago about that issue! Betty's bus was one out of a few at that particular district that needed a transmission replacement.
Edited by - B. Busguy33 on 03/17/2003 5:10:46 PM |
|
|
|
cowlitzcoach
Advanced Member
USA
325 Posts |
Posted - 03/21/2003 : 10:32:45 AM
|
Hey Kiddo,
No new bus on the road today can compare to a Crown Supercoach, but what can I say? And if you can't have a Crown, a new IC RE is actually not a bad alternative. They sure seem to be putting them together a lot better than the BB's seem to be the last few years.
As far as spe'cing the bus goes, one can option a bus up from an affordable to/from bus to a very expensive alternative to a motorcoach--an alternative that is not nearly as comfortable or user friendly as a real motorcoach.
The final analysis has to be made on what the expected usage of the bus is projected to be. If it is going to be in flat land to/from service almost exclusively with student count under 50 students per load, the extra cost of a heavy duty type 'D' bus is probably not a good investment. If the same bus is going to be used in charter work on weekends and evenings, of if the student count is going to be more than 50 students, and if the ground covered is not flat a heavy duty type 'D' is well worth the $$$.
Whatever you decide to purchase, like most hot rodders, I don't think big HP is a bad thing. When you purchase the big HP engines, it requires you to upgrade the transmission and axles. With the heavy duty transmissions you will almost never experience transmission problems (You saw that on the old Crowns with the HT70 and HT740 transmissions. How many of them did you ever see breakdown?). With the heavy duty axles you get bigger brakes. Bigger brakes mean you don't wear them out as quickly, they fade much slower, and when you have to stop quickly you stop NOW.
As it has been mentioned, if you are going to be doing a lot of hills or a lot of urban stop and go, the further investment in some sort of auxillary braking system is not a bad idea. On my little bus that has a Telma driveline retarder I almost never have to do any brake work, unlike my other little bus that is lucky to get 10K out of a set of front pads.
To answer your question about transmissions specifically, the AT540 series transmissions did very well behind the gas V-8 engines. Behind the diesels they weren't so very good, particularly on hills since they almost freewheel on downgrades.
Since the Allison 2000 is basically an updated electronic version of the AT 540 I would think most of the same problems would occur. The largest problem being it is borderline as to how well matched it is to the higher HP engines. The difference in price to the MD-3060 isn't enough to be worth the hassle the smaller transmission will give you in the long run.
If you do get the gig, let us know. We are all rooting for you.
The only caveat I would give to you is before you spend any money, make sure you will be able to get insurance. Ever since 9/11 the insurance market has gotten very hard with very few writing coverage for buses. Your age or lack thereof could be a problem.
Good luck!
Mark O.
|
|
|
|
Craig Thoricht
Senior Member
USA
177 Posts |
Posted - 03/27/2003 : 03:28:38 AM
|
Hello-
IMHO-
Allison Transmission division of General Motors has made thousands of transmissions most of which were AT 545's. These are an ideal transmission for most, but not all, school bus applications. When you consider how many cycles they go through during their working life they are a bargain.
The MD 3060 is also a terrific transmission. We currently have 10 in our fleet behind Cummins and Caterpillar engines. We went to this transmission because Allison restricts the 2000 models for GVW. When used with their synthetic oil the shift quality is unbelievable. The upcharge is well worth it.
I have to say here that, as a mechanic, I love these automatics. If there is a job I hate it's changing a clutch. I just wish that GM had a little competition and maybe we would see prices come down.
|
|
|
|
busmonkey
Senior Member
USA
86 Posts |
Posted - 04/16/2003 : 4:00:26 PM
|
Yes the allison 545 is a 4 speed transmission (good transmission) but the allsion 2000 (excellent transmission) is a 5 speed electronic transmission which means it is electronicly controlled with a pcm (power control module) This is an excellent transmission and it is the best match with any electronic engine. We have 3 of 24 buses with the allison 2000 transmission and the rest is the allison 545 transmission. Of the three electronic transmission one is powered by the DT466E engine and the other two by the cummins 24 valve electronic 5.9 engine. This transmission helps get better fuel economy and you will notice less braking needed when going down step grades, since this has a lockup torque convertor. Plus maintaince is a lot easier on the 2000 series, all is needed is to drain the oil in pan and install a new spin on filter, recomend using and oem filter (don't forget to transfer the magnet from the old spin on filter). One less quart then the 545 for the shallow pan and 6 less quarts then the 545 with a deep pan. In turn you save time and money and get a better performance from the bus.
|
|
|
|
busmonkey
Senior Member
USA
86 Posts |
Posted - 04/16/2003 : 4:05:42 PM
|
This is standard to have some rough shifting with the ISB engine and the allison 545 because you have and electonic engine and non-electronic transmission. If you had the same set up but had a 2000 series trans. it would shift very smoothly!quote:
I'm not that familiar with the 2000 transmission, but I think that it and the 545 are maybe a little light for a DT466, especially if you want any horsepower or torque. My feelings are that you would be happier with the World Transmission, probably the MD 3060. I have the AT545 in a 1999 with a smaller ISB Cummins, and have had problems with rough shifting. I have 3 Worlds, two with 280 HP Cummins' and one with a 250 HP DT466E. All the transmissions have been great, but I prefer the Cummins over the DT466E, but that might largely be due to better service at Cummins. And I might as well say it, the two are in BBAARE's and the other is in an Amtran FE, all 84 passengers. My drivers will all tell you that they like the BBAARE's the best.
David Peil
|
|
|
| |
Topic |
|
Allison Transmission + Int'l Engine Question
