Best motor and transmission combo?

[DaveShoop]

Hello

I am currently looking to purchase my first bus and convert to skoolie. I have read a bunch on here and online about the older busses (2004 and below) being better as far as motors then newer models. Looking at the auction sites it seems the older buses are in rough shape a lot of times either rust or not running. I have seen some 2007-09 Thompson buses with the 8.3 Cummings but can’t find alot of reviews. Was hoping to get some input on 2000-2010 school bus motor and transmission what people thought was the best. Also I will be trying to find a full size bus as I am a family of five.

Thank you for any help or advice.

[Dbacks2k4]

Originally Posted by DaveShoop

Hello

I am currently looking to purchase my first bus and convert to skoolie. I have read a bunch on here and online about the older busses (2004 and below) being better as far as motors then newer models. Looking at the auction sites it seems the older buses are in rough shape a lot of times either rust or not running. I have seen some 2007-09 Thompson buses with the 8.3 Cummings but can’t find alot of reviews. Was hoping to get some input on 2000-2010 school bus motor and transmission what people thought was the best. Also I will be trying to find a full size bus as I am a family of five.

Thank you for any help or advice.

That's kinda like asking Coke or Pepsi?
But kudos for doing your research and asking good questions before jumping in feet first.

I assume you've seen this chart? It's a good reference guide.
https://docs.google.com/spreadsheets...eiVKseLAff6p/9

Oversimplifying things (there are exceptions and different OEMs adopted different things at different times)....
<1997 all mechanical no computers
1998-2004 - electronic engines, no emissions
2005-2008 - EGR emissions control
2008-2010 EGR/DPF emissions control
2010+ EGR/DPF with DEF

it all depends on what you're comfortable with. Personally I'm a big fan of the DT466e with EGR from 2005-2007 paried with an Allison 3000. Some call me crazy for getting into computerized engines with emissions control. I prefer the electronic sensors and have *ways* of making the EGR system no longer cause me issues

[TucsonAZ]

Originally Posted by DaveShoop

Hello

I am currently looking to purchase my first bus and convert to skoolie. I have read a bunch on here and online about the older busses (2004 and below) being better as far as motors then newer models. Looking at the auction sites it seems the older buses are in rough shape a lot of times either rust or not running. I have seen some 2007-09 Thompson buses with the 8.3 Cummings but can’t find alot of reviews. Was hoping to get some input on 2000-2010 school bus motor and transmission what people thought was the best. Also I will be trying to find a full size bus as I am a family of five.

Thank you for any help or advice.

Currently 13 hours left on this, I bet it will go under $5,000 which is an amazing deal for somebody!


https://www.publicsurplus.com/sms/au...ew?auc=3169342


That said, I have a 2002 8.3 and it was for me the "best" choice.

[Sehnsucht]

I will reiterate kudos for asking BEFORE you make a blind leap into a costly mistake!

Coke versus Pepsi, this is a very good analogy. There's probably no 'best' engine, only the devil you know and love. The whole mechanical versus electronic comparison usually relates to those who turn their own wrenches because with at least a basic understanding of diesel engines any mechanical issues is just that - mechanical. But as soon as you add a computer to the equation that gets much more complicated and often expensive. Electronics also limit your ability to do work yourself unless you're willing to spend thousands on diagnostic machines to troubleshoot those electronics which means now you're at the mercy of a diesel mechanic or *gasp* dealership. So I think there's two questions you need to ask yourself:

1. Am I going to learn to work on my own diesel equipment?

2. If no, who am I going to take my diesel equipment to for work and what models do they know well?

If yes to #1, stay as mechanical as possible and deal with the age and rust that usually accompanies that era. Try to get something from the southwest or Pacific Northwest which usually see less rust than Midwestern or east coast. Prepare to spend more for these and plan on having it professionally inspected BEFORE you buy it. If it's roadworthy plan a nice long slow maiden voyage home, anticipating not everything is going to be new car perfect and it may need to be babyed that initial trip.

If #2, the basic rationale is whatever your mechanic knows well, buy that. If he/she's a whiz with Navistar engines, look for ICs which are mostly IC/Navistar engines. If the mechanic is leery of CAT engines but you have your heart set on a bus with a CAT, just be aware your mechanic is going to either shy away or drag feet or spend way too much time researching because that's not their forte.

As for transmissions, well there's not a lot there to discuss, it'll be whatever comes in your bus. As long as it's not an AT545 you should be fine for most any build out. If down the road it's not up to the task a transmission swap is totally feasible but not cheap. My personal philosophy with transmissions is run them until they die because the cost to repair or replace is about equal. That's just me but I've never had good results from rebuilds.

Hope this helps and good luck!

[rossvtaylor]

Originally Posted by TucsonAZ

Currently 13 hours left on this, I bet it will go under $5,000 which is an amazing deal for somebody!

This was a Blue Bird with an 8.3 and an MD3060...pretty much the "best" drivetrain, according to some. I happen to be a fan, myself. Reasonable miles...I think about 120K...and an Arizona rust-free bus from a school district with a good reputation.

I watched the auction until the last rounds and quit watching as a couple of bidders battled back and forth, increasing $100 each time. After about 5 time extensions, it was at $3900...which is where I wandered off. But I'll bet Tucson's right, that it went for under $5k.

It always surprises me that apparently great buses are sometimes hard to sell for reasonable prices, like the similar bus (with the bonus of storage bays and highway gearing) that I helped our local school sell for $2000. But then, folks will list a bus with a lesser engine and an unidentified tranny for $17K because they took the seats out and stripped the walls and painted the floor...and those will sell. Nuts...

[cadillackid]

Originally Posted by rossvtaylor

This was a Blue Bird with an 8.3 and an MD3060...pretty much the "best" drivetrain, according to some. I happen to be a fan, myself. Reasonable miles...I think about 120K...and an Arizona rust-free bus from a school district with a good reputation.

I watched the auction until the last rounds and quit watching as a couple of bidders battled back and forth, increasing $100 each time. After about 5 time extensions, it was at $3900...which is where I wandered off. But I'll bet Tucson's right, that it went for under $5k.

It always surprises me that apparently great buses are sometimes hard to sell for reasonable prices, like the similar bus (with the bonus of storage bays and highway gearing) that I helped our local school sell for $2000. But then, folks will list a bus with a lesser engine and an unidentified tranny for $17K because they took the seats out and stripped the walls and painted the floor...and those will sell. Nuts...

from what i can tell alot has to do with distance... so here are people that want to buy a bus and travel the country all over 10s of thousands of miles.. .. yet dont want to buy one , travel 1000 miles to get it and drive it home.. so instead they buy one close with a lesser drivetrain and way more $$ than the fuel and plane tickets to go get a superb traveller from farther away..



*ALL* of my current drivers have come from more than 1000 miles away... and overall for sure am glad i went those distancesa to get them.. probably most pleased with the 1978 that came from 2800 miles away

[cadillackid]

in All of my bus purchases I have found locals and the sellers to be more than happy helping me get from either the airport or rental car place to my bus to pick it up..

[Dbacks2k4]

Originally Posted by Sehnsucht

I will reiterate kudos for asking BEFORE you make a blind leap into a costly mistake!

Coke versus Pepsi, this is a very good analogy. There's probably no 'best' engine, only the devil you know and love. The whole mechanical versus electronic comparison usually relates to those who turn their own wrenches because with at least a basic understanding of diesel engines any mechanical issues is just that - mechanical. But as soon as you add a computer to the equation that gets much more complicated and often expensive. Electronics also limit your ability to do work yourself unless you're willing to spend thousands on diagnostic machines to troubleshoot those electronics which means now you're at the mercy of a diesel mechanic or *gasp* dealership. So I think there's two questions you need to ask yourself:

1. Am I going to learn to work on my own diesel equipment?

2. If no, who am I going to take my diesel equipment to for work and what models do they know well?

If yes to #1, stay as mechanical as possible and deal with the age and rust that usually accompanies that era. Try to get something from the southwest or Pacific Northwest which usually see less rust than Midwestern or east coast. Prepare to spend more for these and plan on having it professionally inspected BEFORE you buy it. If it's roadworthy plan a nice long slow maiden voyage home, anticipating not everything is going to be new car perfect and it may need to be babyed that initial trip.

If #2, the basic rationale is whatever your mechanic knows well, buy that. If he/she's a whiz with Navistar engines, look for ICs which are mostly IC/Navistar engines. If the mechanic is leery of CAT engines but you have your heart set on a bus with a CAT, just be aware your mechanic is going to either shy away or drag feet or spend way too much time researching because that's not their forte.

As for transmissions, well there's not a lot there to discuss, it'll be whatever comes in your bus. As long as it's not an AT545 you should be fine for most any build out. If down the road it's not up to the task a transmission swap is totally feasible but not cheap. My personal philosophy with transmissions is run them until they die because the cost to repair or replace is about equal. That's just me but I've never had good results from rebuilds.

Hope this helps and good luck!

This is all spot-on tips and info.

My choice of the 06 DT466e with EGR came down to a few things. First, that's what I standardized my party bus fleet on based on the recommendation of my mechanic friend.

His first choice would've been a fleet of 12-valve Cummins, but you can't get those on an IC and I had ruled out BlueBird because where I live you can't get Bluebird OEM parts quickly or easily which we tended to need more than Cummins OEM parts. International dealers are a dime a dozen. Plus (at the time) he was a mechanic for one of those International dealers and could pickup my parts on his way from work...
So his second choice was the Navistar 7.6 which is what we bought a fleet of. He actually prefers the 2004 and older without EGR but was more than happy to teach me how to "permanently fix" my EGRs
So when I sold off the party bus business and fleet and bought my conversion rig, the 2006 IC CE300 with the larger 245HP 7.6 DT466e and the bigger Allison 3000 is what I bought. Took forever to find but I don't regret it for a minute. I could've done <04 without the EGR, but those were on AMTRAN bodies that rattled and have extremely unreliable dash gauge clusters lol. "Fixing" an EGR was easier than rewiring an entire dash in my opinion - plus I like the curved looks of the 05+ IC body.

The point about expensive diagnostics is spot-on. Fortunately Navistar makes ServiceMaxx available for free for pre-Maxxforce engines so a cheap laptop and a NexIQ (not exactly cheap unless you go the Chinese knock-off route) makes for DIY diagnostic capabilities that you just can't get on Mercedes, Cat, or newer Cummins without getting Chinese knockoff software. I can't spit on the Chinese knockoffs too bad - I use a Chinese knockoff version of Allison DOC to tshoot my transmission.

Over the past several years my friend has taught me a lot - I went from being a computer nerd who could barely replace a battery in my pickup to being a computer nerd who is able to diagnose and do most simpler diesel repairs. My mother is still astonished. I draw the line at opening up the valve cover yet, but my friend tells me I've seen him replace enough injectors that I could do it myself. There are a ton of good YouTube resources as well. A willing attitude to get dirty and learn, as well as a good teacher is huge and will save big bucks at mechanics shops or worse, dealers.

What I've also learned is that most non-dealer shops lack the diagnostics to work on electronic engines. That AAA Bus in Phoenix that everyone raves about is the same way. At the time my bus was sputtering and losing power but not throwing a code. The tech was dumbfounded as I tried to explain what I was seeing in the ICP charts in Servicemaxx. He accused me of messing up the ECM with one of those "bluetooth monitors from china" and sent me to the dealer to get the ECM re-flashed which I knew was complete BS. The dealer diagnosed a failing (but not yet totally failed) EGR valve that was causing the sputtering and random issues. I promptly "fixed" myself after I thanked them for the diagnosis with a large check (but not nearly as large as it would've been to have them fix it).

For transmissions, I'll add in be weary of non-Allisons, especially Voith. They're pretty common in transit buses but there's not much aftermarket support for those since they're almost exclusive to government-owned fleets.

[Veloc]

Originally Posted by cadillackid

yet dont want to buy one , travel 1000 miles to get it and drive it home.. so instead they buy one close with a lesser drivetrain and way more $$ than the fuel and plane tickets to go get a superb traveller from farther away..

This is understandable. Not many people want to risk breaking down a thousand miles from home with no idea who to call on the highway. And, heavy equipment tows may take several days to even arrange. The great majority of people that would be interested in building out a bus work at a fixed location for a living, and can barely take enough time off work to get the bus home if everything goes perfectly. One hiccup, even a minor one, and they might have to choose between abandoning the bus somewhere or losing their job. When these are your choices, spending more for the bus next door that isn't exactly what you want looks more attractive than going to the other coast for the perfect bus at the perfect price.


Course, that doesn't apply to everyone, but does apply to the great majority.

[cadillackid]

sure breakdowns are a possibility.. I had a brand new pickup light off into a ball of fire once... somehow waiting days for a tow? ha! I suppose if you travelled in some totally remote area way way off the beaten path.. but along any of the interstates you can get a heavy dudty tow within a couple hours.. or even a mobile mechanic / tires / etc... truckdown is full of places.. thus why many adivse sticking to major routes on your way home.. yes it could happen and yes it could cost $$.. same as it could happen when you are on a trip after converting said bus (from, what ive seen the majority dont send their busses to full-service mechanics upon purchase even when bought close to home)... they get home and convert and do basic maintenance like oil change, make sure the tires are safe, lube, and go..

[LargeMargeInBaja]

Our 1997 has a 505ci/8.3-liter (litre) mechanical.
Allison 3060.
.
At 52mph in the slow-lane, we rarely get better than 14mpg.
.
We are pretty sure this's the best for us, for our purposes.
Nearly two decades full-time live-aboard.
Boondock exclusively, Baja beaches regularly.

[1dmpo]

A lot of info here says 2004 is the cut-off year for no emission buses, but.... anything with a 5.9 Cummins will have no emission crap on it. Cummins didn't add any of the EGR, DPF or anything else until they upped the displacement to 6.7litres. That change didn't happen until 2007.5 so a lot of 2008 model year buses will have a 5.9 Cummins in them and be emissions free.

[cadillackid]

Originally Posted by 1dmpo

A lot of info here says 2004 is the cut-off year for no emission buses, but.... anything with a 5.9 Cummins will have no emission crap on it. Cummins didn't add any of the EGR, DPF or anything else until they upped the displacement to 6.7litres. That change didn't happen until 2007.5 so a lot of 2008 model year buses will have a 5.9 Cummins in them and be emissions free.

every manufacturer met ther emission requirements in different ways.. the requirements took effect in 04 and everyione had to meet them.. and again the 07/08 requirements etc..



cummins got it right as the 6.7 became the true goto of most medium duty vehicles in the US.. all the school bus manifacturers offer the 6.7..



im not sure what changes were made in 04 to the 5.9 but its possible they did it all with the computers and didnt have tpo make physical changes to the engine like others did.

[Sehnsucht]

The other thing that can be a little confusing right around the 2004-07 EPA requirements is that the chassis manufacturer only had to comply with whatever mandate when they built the engine and chassis even if the bus body manufacturer didn't build the rest of the bus until a subsequent year and then label it as newer model year. Hopefully there aren't too many of these unicorns running around but it was multi-year transition period so anything could have transpired. Also I don't think the actual mandate went into effect until 2007 model year but school buses were early adopters unless maybe some school district specifically requested non-EPA2007 models for whatever reason. They would have known they couldn't get away with it forever but postponing the adoption a few years means they could probably avoid the headaches that accompany these emissions systems as long as possible. And with school buses in service up to 15 years that means those final non-emission buses are just now out of service.

[cadillackid]

school bus model years are WIERD.. ive seen 2024! models out already... obviously thiose busses will have 2022 chassis on them...



my superior is the only bus with the same year chassis / body (1978 built in aug 77).. engine was built just a few moinths prior


my 91 carpenter has a 90 chassis.. my 00 bluebird has a 99 chassis with a 99.5 serial number engine..

[dbsoundman]

Just to add a bit about engines... I've learned a LOT about Caterpillar engines after getting my C7, was confident in choosing a C7 when I bought my bus despite the "haters", and am still generally happy with my C7.

But if I had to do it all again, I'd get a Cummins diesel, even a 5.9 (which I think is actually pretty close in power to the C7). Cummins shops and mechanics are EVERYWHERE, and independent mechanics are generally comfortable with Cummins, especially the 5.9 since it was so common in trucks too. Cat, not so much. I'd venture to guess that the DT466 isn't going to be quite as popular in shops as Cummins either. Plus depending on where you look you'll find people either LOVE the DT466 and HATE Cat, or the opposite.

I will say, computerized diesels can make diagnostics and troubleshooting easier IF you get a Nexiq and the associated software for your engine manufacturer. I am another computer guy turned shade tree mechanic, so I'm very comfortable and interested in using the diagnostics to tell me what may be going on. Caterpillar's software will actually log basically any sensor reading you want to a graph, so you can set it up, go for a test drive, and try to capture that weird issue that only happens in X condition on the road.

[cadillackid]

pretty much all the software will do trip reports, the newer the engine the better the onboard diagnostics and on-ECM data logging.



early flash memory was very unreliable in the context of very few write cycles till it was physically ruined.. so logging data on an ECM within itself was very sporadic and usually limited to tattle-tale events such as overheats or under-oil pressure and of course codes and hours / miles..



some ECMs used battery backed RAM instead of flash.. and assumed a lithium battery would last 5-10 years then be replaced (requiring the dealer to reflash the computer)..



I do agree with cummins in the fact that the 5.9 was used everywhere.. the dodge version was ab it different as ot has to support OBD-II for consumer vehicles.. however there were so many box trucks / busses / step-vans that got the 5.9, the T-444E (powerstroke 7.3) was the same on the IH side.. that engine went into literally everything.. the community support for cummins 5.9 and IH 7.3 still remains very strong even though the engines have been out of production for a long time.. 18 years for the 7.3 and about 15-16 for the 5.9


theres so many aftermarket pieces and parts for these engines versus the CAT motors.. it makes parts prices a little more reasonable

[musigenesis]

Originally Posted by cadillackid

the community support for cummins 5.9 and IH 7.3 still remains very strong even though the engines have been out of production for a long time

Do you think the support for the dt466e is still there generally? I've had no trouble finding mechanics to work on mine, but I live in the burbs of a large city.

[cadillackid]

Originally Posted by musigenesis

Do you think the support for the dt466e is still there generally? I've had no trouble finding mechanics to work on mine, but I live in the burbs of a large city.

the 466E has support amongst the medium duty "community" but only a small subset that arent commercial operators.. with the 5.9 and 7.3 having been sold in pickup trucks theres a huge number of them out there with aftermarket parts..



the 466e sold many but all in commercial. so you have good commercial shop support because commercial trucks have al ong life.. money-makers wil get run in-service until they no longer make money.. since the 466 is a wet-sleeve engine they can theoretically keep getting rebuilt forever unless they suffer a catastrophic faiure that destroys the block.. so I expect to see parts and service for them around for a good while yet.



the 5.9 and 7.3 arent wet-sleeve engines.. although you can service-sleeve either.. but theres so many that no one does sleeve em.. you just get another block.. the 6.0 (VT365 in IH speak) also has good community support even though its run was much shorter than the 7.3, but they got a bad rap as there were issues.. issues that for the most part the aftermarket "fixed".. but still.. and the 6.4? (maxxfroce 7).. ha.. the community "support" on the forums for those is "dont buy it!"..written to someone entering in that says "im looking at a..."..