trying to figure out transmission model

Tcbitt_PNW · 09-12-2021, 12:40 AM

Hi all -
I'm looking at purchasing a 1999 Bluebird bus with a 24valve diesel Cummins engine. Problem is, I'm not sure which model Allison transmission it is, and the owner hasnt gotten back to me yet about what it is.
Since it is a 24 valve cummins, would it be safe to assume its NOT an AT545?
Im trying to avoid an AT545 since I plan on taking this bus all over the country.
Thanks

musigenesis · 09-12-2021, 07:47 AM

Have you seen or do you have a picture of the shifter?

Booyah45828 · 09-12-2021, 09:30 AM

Got a vin? You can look up specs here Unit Dashboard | Portal

Booyah45828 · 09-12-2021, 09:30 AM

As far as it not having an at545, many isb cummins engines were mated to an at545, so you can't rule it out strictly because it's a 24v cummins.

Tcbitt_PNW · 09-12-2021, 12:10 PM

Update, owner was able to send me pics. It’s a MD3060

musigenesis · 09-12-2021, 12:25 PM

Quote:

Originally Posted by Tcbitt_PNW

Update, owner was able to send me pics. It’s a MD3060

Aw, too bad ... that's only the best transmission there is.

Another question to ask the seller is whether the 6th gear on it is unlocked or not. Also ask what the rear gear ratio on the bus is, as these two together will determine what your optimum highway cruising speed is.

Tcbitt_PNW · 09-13-2021, 12:26 AM

im not sure the owner knows what they have actually. Any way for me to check engine size? Seeing it in person tomorrow. Or how to determine if the 6th gear has been unlocked? I guess worse case scenario if its not unlocked I can always do that later.

o1marc · 09-13-2021, 11:37 AM

Quote:

Originally Posted by Tcbitt_PNW

im not sure the owner knows what they have actually. Any way for me to check engine size? Seeing it in person tomorrow. Or how to determine if the 6th gear has been unlocked? I guess worse case scenario if its not unlocked I can always do that later.

When you turn the key on the digital display should show a 6 in it. Pull the engine cover, or inspection cover and there should be a visible tag with engine info.

BamaBus · 09-13-2021, 11:53 AM

Did you use the link Booyah gave you? Even if you did I would crawl under the bus to look at the label on the 'passenger' side of the transmission.

Booyah45828 · 09-13-2021, 03:56 PM

Quote:

Originally Posted by Tcbitt_PNW

im not sure the owner knows what they have actually. Any way for me to check engine size? Seeing it in person tomorrow. Or how to determine if the 6th gear has been unlocked? I guess worse case scenario if its not unlocked I can always do that later.

Best thing to do when purchasing a bus from a seller that isn't sure of what they have is to run the VIN or body number through the bluebird link I gave you. That will show what the bus left the assembly line with. Through the years, it might have changed, but that's a small chance. Much higher chance as to the seller not knowing what they have, or embellishing the options hoping to make more with a sale.

Once you're there to purchase, a quick check can verify that it is indeed what the specs list it as.

I assume you're engine size question is in reference to 5.9 vs 8.3? If so, look at this post Here

If it's an md3060, the difference between 5 and 6 is in the software, to check it, start it up, put it in drive, and see if a 5 or 6 lights up.

John 321 · 09-22-2021, 03:29 PM

Find the tag with the transmission serial number then enter the number on the Allison web site in the My Allison section. It will give you the model

EastCoastCB · 09-22-2021, 03:32 PM

Quote:

Originally Posted by Tcbitt_PNW

Hi all -
I'm looking at purchasing a 1999 Bluebird bus with a 24valve diesel Cummins engine. Problem is, I'm not sure which model Allison transmission it is, and the owner hasnt gotten back to me yet about what it is.
Since it is a 24 valve cummins, would it be safe to assume its NOT an AT545?
Im trying to avoid an AT545 since I plan on taking this bus all over the country.
Thanks

Most buses of that era would be a 545. If its a high hp engine then maybe a 3060.
Always verify what transmission you're getting- MANY sellers will outright lie about that to sell a bus.

If its a shorty a 545 isn't really that bad. Wouldn't want one in a forty footer though.