Swap a B 500 for a 740 allison

[alltech]

I know that this has probably been talked about before, but I can't seem to find a tread on it. Anyway, I have a 740 Allison behind a 8V92. Although there is lots of power, it doesn't seem to have the correct passing gear on the highway. I live amongst a bunch of 2 lane highways that have hills and curves and you can get trapped behind slower moving units if you don't have the jam to pass in shorter distances. I have been told that the B 500 is a better transmission for this and I am wonder few things.

1. Is it possible to bolt a B-500 up to a 8V92?
2. Will the B-500 fit in place of the 740?
3. I have a DDEC II, do I require an upgrade computer up to do this?
4. Is there any other show stoppers?

Thanks for your help!

Regards,

Ross

[John316]

Ross,

Sorry, I can't answer your other questions. But, I do know that the B500 is a neat tranny. If we want to pass on a two lane road, we can do it. That tranny is really nice. We can hit...no I won't say how fast we can push it .

Sorry that didn't really answer your question. I do know they are very expensive. And I do mean VERY expensive.

God bless,

John

[Don Fairchild]

The B500 does not work as well on DDEC II as it will on III or higher. They make a two to four up grade. You will need to change your gear ratio. My gillig  has 4:46 gears with 24.5 tires  I have a 8V92 set at over 500hp and it pulls my chevy 3500 4x4 crew cab all over the country. Just ask the real BK and Uncle Ned.

Don

[alltech]

Thanks Don

I will check my diff ratio, do you know if this is just a software upgrade or a complete harness change and ECU?

[Busted Knuckle]

Ross,
While a B500 will help, it's not going to help that much! Yer talking 25,000 pounds here not 2,500!
While I agree with John, a B500 and 60 Series are nice it still takes time and space to get a 25,000 + vehicle moving at a substanially different rate of speed than what it is currently doing!
Trust me I ain't try'n to blow smoke here we have 5 (yes count them 5) 500+/- HP 60 Series buses with B500's and it still makes me nervous and I have to wait looooonnnggg periods of time for just the right moment to pass!
And for the cost of the swap I don't see it justifiable!

As Don says his 8V92 is set at OVER 500 HP also, and he can vouch that even with a B500 it's not going to turn your bus into a 1/4 mile terror! (well maybe if yer name is ED )
FWIW JMHO!
  BK    (the politically incorrect busnut! )

[Hard Headed Ken]

I think BK is correct, I'll just add some more information that may help make your mind up.
I'm sure the B500 will bolt to the 8V92 bell housing, it's a standard SAE bolt pattern. According to the Industrial Automatic website, the B500 is 3.4 inches shorter than the HT740. What you will have to be careful of is the diameter of the B500, it's fatter than the 700 series.
I'm not saying it's a bad transmission, but it's not as durable as the 700 series. If you talk with people who own entertainer or charter coaches you'll find B500's failing at 300,000 miles is not uncommon and anything lasting over 500,000 is rare.  Just be careful buying used ones, it's about $9000 for a B500 rebuild. 
The B500 has a .64 over driven ratio in 6th gear. I think you would need something like a 5.00 differential ratio. I don't think you would want to run a 2 stroke much lower than 1600 RPM's at 70 MPH. I'm just making an experienced guess at these numbers. You need to calculate the RPM verses speed based on tire size and the exact diff ratio available for your bus.  Your bus probably has  somewhere between a 3.30 and 3.73 differential ratio now.
I think you would need to change you ECM to a DDEC IV. I think the B500 needs the J1939 terminals offered in DDEC IV in order to communicate with the engine. Detroit offers a conversion harness kit, allowing the upgrade from DDEC II to IV and it's not very expensive for the harness kit, although the DDEC IV ECM and reprogramming will not be cheap.
I don't know if the B500 requires more cooling, maybe someone else can answer that.
Ken

[RJ]

Ross -

Help me understand your thinking here. . .

You want to swap out one of the most dependable automatic transmissions ever built for an expensive, shorter-lived, electronically-controlled five/six speed automatic simply because you want to shave a few seconds off your passing times?

Is this right?

Having a hard time wrapping my industry-experienced brain around your idea. . .




PS:  Consider re-reading Aesop's Fable about the tortoise and the hare???

[luvrbus]

Alltech, if you don't like the shift pattern and points of shift on your 740 take it and have the shift points changed not that big of a deal also a Stone/ Bennett shifter helps just a flip of the old switch for another gear. love mine



good luck

[belfert]

The B500 does not require J1939 communication at least not with the WTEC II.  My DDEC III doesn't have anything plugged into the J1939 port.

[luvrbus]

Yours must be just using 5 speeds of the 6 speeds like Don said they don't work good on a DDEC II but they will work


good luck