Engine and transmission reliability?

[IAmCanadian]

Hey!

So currently I am looking at the coach market, specifically MCI and the 102A3, 102C3, and the D series.

Something is kinda bugging me... why do they all have rebuilt engines or transmissions? I mean these are very expensive repairs. Are bus companies always having to do rebuilds on their machines? I thought these machines were supposed to last 1-3 million miles. I would assume that would mean without $15,000 repairs.

What is causing these engines to need rebuilding all the time?

I understand a commercial operator will put significantly more milage on a coach, but have any of you had to rebuild either an engine or transmission?

John

[luvrbus]

Buses are hard on engines if operators or bus lines get 500,000 miles from a engine or 300,000 from the World Transmission they are over joyed to say the least,million mile buses with no major expense priceless

good luck

[chev49]

Most of them are run ragged...

[artvonne]

  I think he needs a better explanation.

  I rode a Bus out to Denver when I was 17. Somewhere across Nebraska and bored out of my mind I went up front and struck up a conversation with the driver. How bad are these on fuel? How far do they go on an engine? Clutch? Transmission??

  His answer struck me odd, but over time I found its the Gods honest truth. It depends.

  A guy can burn up a brand new clutch within minutes. Another can make such jerky and hard shifts they can break parts inside the transmission. Run an engine out of oil, any engine, and it may stop within minutes. Or less. I saw a large Semi tractor that the driver twisted the driveshaft in two, trying to pull a stuck trailer out of a spot.

  On the other hand, a guy who knows how to work a clutch properly just about cant wear one out. Maintain the engine and keep good oil in it, and drive it right, and many often far surpass the average life expectancy. Ive seen Mercedes diesels with over 500K on the odometer. Same with some Ford diesels with the 6.9 and 7.3. Ive heard some of the Cummins in Dodge trucks have gone just as far.

  Detroits are huge engines with huge parts and they wont tolerate hard shocks well. The flywheel itself is so heavy you cannot pick it up. Forcing it to make sudden speed changes from jerky shifts can litterally twist the crank in half. The automatic transmission likely extended the life of a lot of big truck engines simply by taking out the potential for large shocks hitting the engine. That same jerky driving can break transmissions, twist driveshafts and destroy rear axles.

  There are some old Buses with Detroits out there that are 40 years old or more with nearly a million miles that are still running. There are also late model Buses sitting around broken. Just depends on who's been the nut behind the wheel.
 

[RJ]

John -

Welcome to the board!  Lots of info here, lots of hot air, lots of blowing smoke, lots of tales of woe, and lots of tales of joy.  Crazy community of people involved in what many folk's minds is an insane passion.  Won't be too long and you'll figure out who the main characters are on this bbs, and then it will be time for you to join the fun!

Now, to give you some additional perspective on your question, the correct answer is:  It depends!

If the coach is used as a commuter with a lot of stop/go short runs, 150K > 250K is about normal for a powertrain pushing this much weight.

If the coach is used more as a tour bus, with 300 > 400 mile days, plus a lot of idle time at the tourist trap, then 300K > 500K and it's powertrain overhaul time.

Greyhound for years has figured about 400K > 500K miles per powertrain, and they usually do a complete swap at that time (engine & transmission).  They also figure 100K on a set of brakes.  When their fleet had mostly 2-stroke Detroits, the engines would have the rack run every 100K, too.

Speaking of Greyhound, I'm not sure what their policy is today, but at one point when they received a new coach, it's first assignment was on the transcontinental runs - the coach would cover about 21,000 miles a month.  At that pace, in four years the chassis hits the one million mile mark, and Hound typically keeps a coach 10 years.  Now, the annual mileage tapers off as the coach ages, but it's not unusual to find a Blue Pooch being sold to a second-tier operator with over two million miles on the chassis, and most likely it's fourth powertrain.

Tour buses typically have fewer chassis miles on them than the line-haul Greyhouds and Trailways, but more than the commuter cars.

Automatic transmissions have greatly increased the overall life expectancy of a coach powertrain, even with the slight fuel economy penalty.

In RV service, and with proper care, the powertrain will outlive you 90% of the time.

In your search, look for a C or D model - both are 102" wide, but they also have a 3" higher roofline, thus no roof raise needed.  Run, don't walk, away from any "G" models that you might find, that's a POS specifically designed by a Greyhound committee consisting mostly of bean counters.

FWIW & HTH. . .

[belfert]

Considering the $400,000 to $600,000 cost of a new coach, the cost of a rebuilt engine and/or transmission is not all that great.  I suspect that today's engines will last longer than the 2 strokes.  Tranmissions are still a 300,000 to 400,000 mile item.  The coach itself will last 1 to 2 million miles, but it won't be without replacing some parts along the way.  People wonder why a charter costs $3 a mile and up and this is part of the reason.

I need a repair on my B500 and I was debating if I just replace the whole thing since it has between 350,000 and 400,000 miles on it.  I've decided on the repair and will hope I can get another 50,000 miles out of the transmission.  My worst fear would be the transmission going out on the road and having to pay an arm and a leg for a new one.  There is a local guy who rebuilds B500s pretty reasonable or I can get a remanufactured one for $6400 built by a large local company so no freight.

[demodriver]

Artvonne hit the nail on the head IMO. Any drivetrain will last accordingly to how it's treated. For examole my last cummins truck was a 93 model and had well over 500k on it. The drivetrain is actually in a museum somewhere now. It still ran and drove great and the motor and tranny never had any major work done. My current cummins truck has 350k on it and still runs strong without any work on the engine. It did have a auto trans replaced 14k ago. But they are all junk in these dodges. 

With good maintenance and respect to thedrivetrain it's amazing the mileage you can get out of a vehicle. No matter what it is.

[Len Silva]

John,

You have to consider that when these coaches hit the used market, they have lived the best part of their economic life.

At some point the operator figures that they have spent $100,000 on maintenance to get the first million miles, and that was probably just engines, transmissions and brakes.

The next million is going to take the same thing plus failing body integrity, suspension, rust, and appearance issues.  That's when they decide that it's cheaper to buy a new bus.

A friend of mine was a charter operator with 6-8 buses.  He generally bought Eagles from Carolina Trailways with a good record of well maintained buses.  He always budgeted an additional $15-20K over the purchase price to get them back in service.

[luvrbus]

All diesel engine are design to burn X number of pounds of fuel over their life span a bus is under constant load with the AC and other equipment plus they have the dynamics as RJ says of a brick those engines work hard you are not going to get a 1,000,000 miles on a engine in a bus if there was not major work done on a 60 series DD or the Cummins with over 500,000 miles on it I would run from it   

You  cannot compare a diesel car or pickup to a bus I had both Ford's and Dodge's 1 ton diesels with tandem dual goose necks   

You load those to 30,000 lbs everyday of their life like I did they don't run 500,000 miles we got about 200,000 from the Ford's and 250,000 from the Cummins was a wash out when it came to replacement the Cummins cost more to replace than the Ford by a bunch,50 or 60,000 was about it for transmissions and rear gear in both,fwiw the Dodge had the worst transmission for failure,it is not always the driver check some of BK's posts lol


good luck

[artvonne]

  I dont know Clifford. We had a couple 1 ton Ford roll backs with the 6.9, plus two Ford wreckers, they didnt go far without a car or two (or a truckor two) hanging off them, and I personally knew a few salvage yard guys running the same trucks. Everyone I knew was seeing 400K plus out of those engines. We had one that was over 500 on the original motor with no major work, still wasnt using oil and would crank up down to 20F if you forgot to plug it in. I dont think the later engines were as good as those early 6.9's though.

  There is a diesel Mercedes in their museum, was bought new and ran as a Taxi until it reached 1.2 million when Mercedes asked for it back and gave him a new car. This was in Greece, and in europe all their engines are tiny. This was a 1.8 liter diesel IIRC, so wound up working hard all its life, if thats not working hard I dont know what is.

  But your right, a Bus is pulling full power out of the engine most all of the time, and a million would be a tough haul. Companies like Greyhound knew that 400K was a good number to pull them out, all pushing them further would lead to was catostrophic failures. Thats the same reasoning for putting time limits on aircraft parts used in commercial service flying passengers. Replace the part long before you know it will normally fail, so to avoid failure. It doesnt work 100%, because were human and parts dont always last as long as a piece of paper says it will. But its better than the alternative. Back to shock loads though, Tow Boats on the rivers get a lot of hours out of Detroits.

  A lifetime around mechanics has taught me to trust nothing, and nobody but myself. Ive seen engines claimed to be rebuilt that were so screwed up you had to just scrap it and start over. Bus companies dont take Buses out of service for no reason, they keep records and after seeing a Bus begin to start having failures they move on to newer stuff. A few $1000 tows and they could have afforded a newer Bus coming out of service from a higher grade company.

  So you bought an old Bus and know NOTHING what it has going on inside the guts of its engine and running gear. You could attempt to check it over externally and let your ears tell you what they think, or you can tear it down and let your eyes see whats going on, and then know what you have. One way costs little time or money and we go down the road semi blind praying nothing goes wrong. The other way costs a lot more time and a lot more money, but will without question reveal the physical condition of all the internals and there is a virtual 100% chance we'll find something wrong or failing in the process we can fix before it takes off. Neither way will prevent a failure, a part can go south anytime and take out other parts. Thats the nature of mechanical things. But inspections and maintenance have proven to eleviate a great deal of risk. And you need look no further than passenger aircraft to see it work.

  Most of the failures we read about are with old equipment with dubious (or no) records and no one having been inside since God knows when. That is simply a recipe for disaster. Far too many buy an old Bus, spend a couple years and a lot of $$$ on the conversion, without ever tearing into the engine to know what they have. Why they are surprised 500 miles from home when it blows up makes no sense. I dont plan on going anywhere until I have a good feel for what I have back there. That means dropping the pan to check bearings, pulling the covers to see the cylinders, removing the rocker covers, and etc., etc.. Likely (maybe) ill pull the motor and check a lot more than that, get a new clutch, but thats the only way to know for sure.   

[luvrbus]

Paul, mine were all 7.3 turbo electronic engines they would eat injectors like one would french fires 

good luck

[JohnEd]

Paul,

Great post.  Thank you.

Can I add something that is mostly impression?  The 2 strokes seem to have been overly sensitive to the driver.  Run wrong, read lugged, they had a very short life span.  Run extremely hard they lasted for many hundreds of thousands of miles.  I think the axiom was to "run the DD like you were really really mad at it and it would last forever".  Baby it and it died.  I think that specifically did not apply to the 4 strokes.

When I first heard it, I was surprised to learn that most shifted the 740 manually so they could keep the r's up and not let it "dog" after a shift.  And the more severe the grade, the more likely they would bump into the governor before shifting.  The way some talk I think they hit the red line before shifting as a general rule.  Dunno!

John

[artvonne]

Paul, mine were all 7.3 turbo electronic engines they would eat injectors like one would french fires 

good luck

  Mine have all been mechanical injection, and from everything ive read you couldnt give me an electronic one. Ive owned over half a dozen of them and other than the junk GM starters I never had any trouble with them. One had about 600K on it and was using a bit of oil, but other than that it ran great. A few I know that lived with the common rail 7.3's didnt have anything good to say about them either. That 6.0 is junk from everything ive heard. Like everything we make, we just keep getting dumber at making things that work.

[artvonne]

  The 2 strokes seem to have been overly sensitive to the driver.  Run wrong, read lugged, they had a very short life span.  Run extremely hard they lasted for many hundreds of thousands of miles.  John

  John, I have leaned so much since joining this site, its really been a fun learning curve. And what you say is what ive read here a lot as well. I had always heard they liked to scream, but I thought it was the Cummins that didnt like being lugged, the thing about staying away from making black smoke was quite interesting to read.

  I'll say this again, I think there is a lot more misinformation out there about Buses and Detroits. Too many people think they are indestructable, that failures and breakdowns are so rare you dont even need to look at the engine, just drive it. But just like other machines, even a Mercedes, they do need care and feeding, and an easy hand, if you expect them to last. Before I was licensed to drive I knew an engine could be destroyed within minutes in the wrong hands. Detroits, Mercedes, Fords, Lycomings, Ferrari's, it makes no difference. They all break. They just break faster in the wrong hands.

[Mex-Busnut]

You  cannot compare a diesel car or pickup to a bus I had both Ford's and Dodge's 1 ton diesels with tandem dual goose necks  

Let's see now, Mr. Luvrbus: "tandem" = "one after the other", and "dual" = "two", so are you towing four trailers at once?

Or maybe the dual goosenecks are as in the photo, being you are a LUVR-bus and all... Just saying...



Sorry. I couldn't resist.