4104 or 4106

[JohnEd]

I know that the 04 has a muffler that will burn the house down when it fails.  What else differentiates these two great old buses?  Why would I want one over the other?

John

[gus]

John,

I fixed the muffler problem once and for all by getting mufflers without the top ridges. I had to do a bunch of welding but it was worth it.

The 4106 is a hot rod and the 4104 is a slug.
The 4104 is all Al and the 06 has steel attached to Al in the body.
It is much easier to install an AT in a 4106.

They are both great buses, the same size and except for the above are very much the same.

I shopped for both and bought the 4104 mostly because it was the first one I found that I really liked and was a reasonable price.

[LarryN 4106]

to me, the 04 has the best looking "bus look" of any bus, and by the far the best looking bus "butt".

[johns4104s]

John Ed,

I have three 4104,s. All I can say is you will have to work on whatever you buy, the 04 is the easiest to work on.
I have never heard of a fire from the mufflers,Thant not saying it could never happen. the 06 is prone to bulk head cracks, all that power, its the sports car of buses,
John

PS You need to buy one of mine.

[buswarrior]

FWIW, the old highway men around here, when given a choice in the snow, would choose the "round back" GM over the "flat back" GM.

"They held the road better" was the best I could be told, my father was one of them.

There are some things that might be better left unexplained and left at face value?

happy coaching!
buswarrior

[johns4104]

To add a little to the above.
The 4106 had a rear anti-sway bar the 4104 did not.
The 4106 used the rolling lobe bellows for the air ride and the 4104 used a standard bellows and air beams.
Also I don't think you would want to add a auto trans to the 4104 and give up any more power.
The 4106 did not have the emergency door, which you gotta admit is pretty cool on the 4104.


John

[zubzub]

When I get to worrying I sometimes wish I had an '06.  The chance of using more readily available engines and difs in the case of an engine failure is the main reason.  On the other hand I find the straight six config to be so easy to work on, when I look at the 8v71 stuffed into the rear of the later GMs it reminds me too much of working on late model GM vans (very tight). On a '04 everything is right there, there is enough power if you're not in a hurry...(I plan to add propane boost in the future to get up the big ones) and it's true the '04 butt is much nicer (the '06 looks a little like a transit...not that there's anything wrong with that).  Also the '04 gets better mileage. 
If I was doing it again it would come down to what was best $ and shape and nearest to me, but if I found 2 in the same shape for the same money right down the block, I would probably choose the '04.  I guess I'm in love

[johns4104]

Zubzub,
I found out from another bus nut 4104 owner that the rear axle is the same.
On the 4106 it is just turned upside down. now the center section however is at a different angle.
Now as far a fuel milage goes. the 4104 has a 1 to 1 angle gear on the trans where the 4106 uses a over dirve of .808 to 1 so if driven carefully the 4106 can get apprx the same milage.
as far a working on it I would much rather change a starter on the 4104 than the 4106!!!!


John just lovin my 04

[uncle ned]

The rear axle on a 04 and 06 is the same but the pumpkin or center section is different.  Takes a little work to put the 06 pumpkin in a 04 but it can be done.

That is what needs to be done to put a 6v92 or a 8v71 and v730 auto.

makes a nice bus

uncle ned

[zubzub]

Slowly I am beginning to understand.  From what I read above...if my dif fails in the middle of nowhere I can use a "06 pumpkin. 
Does that mean I could use the pumkins from other V drive gms....maybe even a transit dif (providing the ratio was right).
Yada yada yada, guess I'll find out IF mine ever fails.....It's weird really with all my old rigs I have usually sourced a spare engine and a spare dif and yet I have never needed them. I  have had only one $$$/inconvenient engine failure years ago in a Renault 5  that car was quite a lousy POS, fun to drive though.

[gus]

Zub,

That 04 rear end is not likely to fail if you keep it oiled, those things last forever.

I can live with the lower speed, we  seldom travel more than 60 mph. My theory is we get to see more that way and I'm sticking to my story!!

I've never wished for an 06 but have thought about a 6V92 turbo with AT. The cost of such a mod has kept my enthusiasm down!

[RJ]

Slowly I am beginning to understand.  From what I read above...if my dif fails in the middle of nowhere I can use a "06 pumpkin. 
Does that mean I could use the pumkins from other V drive gms....maybe even a transit dif (providing the ratio was right).
Yada yada yada, guess I'll find out IF mine ever fails.....It's weird really with all my old rigs I have usually sourced a spare engine and a spare dif and yet I have never needed them. I  have had only one $$$/inconvenient engine failure years ago in a Renault 5  that car was quite a lousy POS, fun to drive though.

Zub -

The answer to your thoughts above is yes, no, and maybe!

Yes in the sense that the stock 04 and 06 both use the same ring & pinion ratio (4.125:1).  There were a couple of additional ratios available as options, but those are very, very rare nowadays.  I'm not really up on transit ratios on the older stuff, I only know you used to be able to order a 4:10:1 R&P from Rockwell/Meritor to fit the RTS pumpkins.

The major difference between the two, however, is that the differential pumpkin is off-set to the driver's side in the 04, and to the curb side on the 06 (and later) model coaches.  This was done when they moved the transmission bevel gears from behind the gearbox in the 04 to between the clutch & gearbox on the 06 and later models.

As you already know, the other major difference is the 04 uses an air beam in conjunction with (originally) convoluted air bellows, while the 06 and later GMs use rolling lobe air springs.

Uncle Ned hit the nail right on the head with his comment that you must install an 06 or later rear axle if you want to upgrade (?) your 04 to an automatic.

OTOH, the 04 falls very, very neatly into that classic children's fable: The Tortoise & The Hare!

FWIW & HTH. . .

[johns4104s]

25 + years ago I had friends that ran and maintained a fleet of 4104,4106,4905 and Eagles. They all without a dought re comended I look for a good 4104 to convert. There reason was that with help I could run and maintain the 4104. I have to say they were right. But I had an awful lot of help from Luke and fellow bus nuts.
The company I purchased my first 4104 from ran 04,s 06,MCI 8,s,9,s, Eagles and Van H. The owner Albert Hotard From New Orleans also said that the 4104 was the easiest to maintain.
I ended up with three 4104,s.

There are an awful lot of rough zero maintained 04,s and 06,s. Be sure you have someone look them over. Buy one converted ,then up grade it.

John

[Old4103]

See if you can find and buy a PD4103, get rid of half the problems that any air ride bus has.

[gus]

Glass is a problem with old buses.

I don't know about 4106 glass but the 4104 rear window is not available but the front windshield is.

The 4103 windshield is not available and probably not the rear either.

3751 and 4151 are the most beautiful and classy but I doubt that any body parts are available.