Best engine/transmission for the high country

[Asantana]

In your humble or not humble opinion, what are some of the best engine / transmission combos for driving a big bus in the Rockies?
I want a beastly 40 footer that can tow a Subaru.
Thanks!

[Tango]

Sounds like you need at least an 8.3, a full locking tranny and even a retarder or Jake Brake. Best place to look for Skoolies that come equipped for the high country is in Colorado.

[johnbloem1974]

1st choice would be either a DT466 or Cummins 8.3 mated with an MD3060 transmission. Next transmission setup would be an Allison 2000 series as it will also have overdrive. If you get an older setup, an MT643 is also a very capable transmission. Run away from an AT 545. Ask me how I know...

John

Sent from my SM-G950U using Tapatalk

[PNW_Steve]

I have to go with the crowd: 8.3 Cummins and an MD3060.

That said, I would not pass up a good DT466 or DT530 if coupled with an MD-3060.

[PNW_Steve]

Here is one for you to look at: 422 Auction Services - Mathies & Sons, Inc.

8.3 & 3060

[Asantana]

Thanks! I found a DT 466 but with an AT 545. So, I'm kinda scared to ask, but how do you know?

[Tango]

If you are going to frequent the High Country...or even a few steep hills...you do NOT want an AT 545.

No lockup will have it overheating (and dying)...no (as in zero) engine braking coming down...and with only four gears topping out at 1:1...lousy MPG's. Plus they are rapidly becoming very difficult to service. I could not give a working one away for free here in Houston...no one wanted it...even as a core.

Seriously...find a another trans.

And somewhere here on the forum is a thread describing how to tell the difference between a 545 and a 643. Other than that, you'll have to go online with some serial numbers. Allison can tell you exactly what it is.

[Robin97396]

I'm also seeing a lot of 466s with 545s. That doesn't sound like a logical combination. A weak trans with a strong motor? Doesn't make sense, yet there it is.

[Twigg]

Originally Posted by Robin97396

I'm also seeing a lot of 466s with 545s. That doesn't sound like a logical combination. A weak trans with a strong motor? Doesn't make sense, yet there it is.

A lot of DT466 are shipped with 195hp. It is an engine that makes servicing easy, and easy rebuilds in a school bus barn, yet can also be partnered with the cheapest transmission.

I guess that's why they were spec'd.

[2martins]

Originally Posted by johnbloem1974

1st choice would be either a DT466 or Cummins 8.3 mated with an MD3060 transmission. Next transmission setup would be an Allison 2000 series as it will also have overdrive. If you get an older setup, an MT643 is also a very capable transmission. Run away from an AT 545. Ask me how I know...

John

Sent from my SM-G950U using Tapatalk

OK, tell me about the AT545 please? I don't live in the rockies but I will have to go over a mountain now and then. I don't mind going slow and pulling over and letting people pass, but is it worse than that? Mine is either an AT545 or 540 - guy is gonna check for me Monday but with a T444e engine. Dear God, I'm clueless!!!! In my defense, my son picked out the bus....

[2martins]

Originally Posted by Robin97396

I'm also seeing a lot of 466s with 545s. That doesn't sound like a logical combination. A weak trans with a strong motor? Doesn't make sense, yet there it is.

is it better if I have a T444e with an A540? cause I think that's what I have. the guy is gonna check. if i do, how do I adjust my driving to compensate?

[Robin97396]

The trick is to treat the transmission nice. It's great if you have a trans temp guage so you can see if your trans temp is getting to high. Just don't drive it wide open while pulling hills. Be that slow guy, because you'll be able to tell when the trans starts not pulling correctly on hills. You'll be running at rpms that don't match your speed and the transmission will heat up quickly. Not emergency quickly, but if you've got miles more of hill to climb you should be watching the trans temp while keeping an eye out for sort of nice places to stop to cool down.

I pull some 5 and 6 mile long hills and rarely get the trans temp up at all, but those are 1st and 2nd gear hills uaually at about 2000 rpm. I'm beginning to get a little clunking between 1st and 2nd as well as turning excessive rpms on hills while on the highway. I'm settling this by looking for a 2000 series transmission before this tired 545 gives out. Actually I'm looking for just about any transmission that will fit that's not a 545. Climbing all these hills also means I've got to go back down the hill. This does not exactly freewheel on downhills but I can understand why it would feel that way in 5th gear at high speeds. In first and second I was getting a fair amount of compression resistance. Enough to greatly reduce the need for braking.

It's an old workhorse transmission with no bells or whistle. It's kind of a go and stop transmission, fairly well suited for a bus or delivery vehicles. They're pretty cheap to replace, or you can pay a bit more for a higher quality replacement like the 2000 that I'm after.

At this point I'm to far in to change buses because of a weak transmission.

[johnbloem1974]

Originally Posted by 2martins

OK, tell me about the AT545 please? I don't live in the rockies but I will have to go over a mountain now and then. I don't mind going slow and pulling over and letting people pass, but is it worse than that? Mine is either an AT545 or 540 - guy is gonna check for me Monday but with a T444e engine. Dear God, I'm clueless!!!! In my defense, my son picked out the bus....

The AT545 is a transmission with a non-lockup torque converter. Basically, there is no mechanical connection between motor and transmission, only a fluid coupling. This kind of setup is OK for short distances and lots of stop/start runs. It is not ideal for towing/highway/mountains. I go back and forth from Texas to Montana 2 times a year, with lots of stuff and towing a car behind the bus. Transmission blew in October and we had to replace it. I upgraded and went with an Allison MT643. This model has a lockup torque converter. Night and day difference on how it drives, especially up and down hills. Basically, It boils down to how you will be using your bus. If you are not doing any towing, an AT545 will be adequate and could give you years of faithful service, just make sure to not overheat it... hope this helps!

John

Sent from my SM-G950U using Tapatalk

[Alvarez]

I am also wanting similar to what OP posted. I came across an ‘04 Bluebird 40 footer that I really liked with a Cummins ISB 5.9L L6 turbo diesel engine. As for the transmission the auction only states that it’s an automatic transmission. I’ll update when I get a reply back regarding the transmission model. Is this engine strong enough to pull a car and make it up hills?

I really appreciate everyone that contributes to this forum, you guys make this place a very valuable resource!


Sent from my iPhone using Tapatalk

[Asantana]

Originally Posted by johnbloem1974

1st choice would be either a DT466 or Cummins 8.3 mated with an MD3060 transmission. Next transmission setup would be an Allison 2000 series as it will also have overdrive. If you get an older setup, an MT643 is also a very capable transmission. Run away from an AT 545. Ask me how I know...

John

Sent from my SM-G950U using Tapatalk

Thank you! Do you think a Cat 3126 paired with an Alison 2000 would do the trick?

[johnbloem1974]

Originally Posted by Asantana

Thank you! Do you think a Cat 3126 paired with an Alison 2000 would do the trick?

Don't know enough about the Cat engine to make a judgement, but that is definitely a good setup transmission-wise...

Sent from my SM-G950U using Tapatalk

[Tango]

Cats are fine...until they aren't. Then they get really expensive.

[PNW_Steve]

Originally Posted by Alvarez

I am also wanting similar to what OP posted. I came across an ‘04 Bluebird 40 footer that I really liked with a Cummins ISB 5.9L L6 turbo diesel engine. As for the transmission the auction only states that it’s an automatic transmission. I’ll update when I get a reply back regarding the transmission model. Is this engine strong enough to pull a car and make it up hills?

I really appreciate everyone that contributes to this forum, you guys make this place a very valuable resource!


Sent from my iPhone using Tapatalk

5.9 in a 40' bus is not going to be a highway screamer. If you really want good highway performance and some towing capacity you are better served sticking with the 8.3 or DT466/530 and an overdrive transmission. Best transmission choices would be the md3060 or the 2000 Series.

Worth mentioning: A few members here with md3060 equipped Thomas buses have had success getting 6th gear unlocked. Those of us who have Bluebird's have not been as fortunate and have 5 forward gears and a single overdrive.

[Kubla]

There are several of these on public surplus, pretty much what you are looking for
https://www.publicsurplus.com/sms/au...ew?auc=2024698

[PNW_Steve]

Originally Posted by Kubla

There are several of these on public surplus, pretty much what you are looking for
https://www.publicsurplus.com/sms/au...ew?auc=2024698

Nice drivetrane. I would be concerned about rust on those. Definitely want to have a look at them before bidding.