04 international DT466E with Allison

[Venturevibesbus]

Good morning,

I have a 2004 international 3800, I’m having trouble getting it to go into gear. My air pressure builds to 120 psi, but when I select drive, reverse, or select gears individually it stays in neutral. The selector panel for the tranny doesn’t blink when I select drive or reverse. My wiring diagram that came on the bus doesn’t match what’s on the bus, so I’d like to find a wiring diagram and how to locate the model of my transmission. I have never worked on a bus, but I was a heavy equipment mechanic, I just need a push in the right direction.

[fo4imtippin]

Your transmission has a silver plate on the side with the model and serial. It's probably covered in oil and grease, so bring a rag..

[Jolly Roger bus 223]

is it a push button shifter or a t handle style ?
does the back light work/illuminate?
electronic shift or cable?

[Jolly Roger bus 223]

in greensboro you are also close to a huge bus barn off of I85/40 near graham/ mebane.
the one time i was working in the area i stopped and talked to them and they had no issue with me being there asking questions.

[Venturevibesbus]

It has a push button

[skoontz]

With a push button pad, it is probably either a MD 3060 or 3000PTS, which seem to basically be the same thing. I had found a troubleshooting guide for the 3000 and 4000 transmissions here:

https://www.trucktransdiag.com/downloads/4gen.pdf

It walks through troubleshooting the wiring, checking codes (even by using the control pad), etc.

The screenshot is of the section that seems to me to best describe your problem, and potential solutions to try.

Good luck!

[Venturevibesbus]

Thank you,
I checked for codes and nothing showed. The air brakes are not releasing and I don't want to cage them unless I have to, I don’t have a maintenance manual and don’t know how many turns it takes to unlock them.

[Jolly Roger bus 223]

are you building air pressure above 90 but more like 120psi?
does the air brake release button stay in when you push it in or does it pop back out immediately?

[skoontz]

If the brakes aren't releasing and the transmission won't go into gear, the problem is most likely an interlock. An open wheelchair lift door (if you have one) could cause this. Open emergency exits and a no child left behind system might also do this, but would also have a buzzer.

[musigenesis]

Originally Posted by skoontz

If the brakes aren't releasing and the transmission won't go into gear, the problem is most likely an interlock. An open wheelchair lift door (if you have one) could cause this. Open emergency exits and a no child left behind system might also do this, but would also have a buzzer.

On my 2003 International, the only thing the interlock does (did) is prevent the bus from starting, and only if one of the deadbolts for the emergency exit doors was locked.

[cadillackid]

Originally Posted by musigenesis

On my 2003 International, the only thing the interlock does (did) is prevent the bus from starting, and only if one of the deadbolts for the emergency exit doors was locked.

schools can spec the busses however they want.. , for instamce in many districts when the bus stop, door is open and reds are on the trans auto-neutrals (allison 3000) and the parking brake is auto applied/.


others have mentiobned wheelchair lifts being open as another reason. . if you took a lift out chances are you broke that system and the bus will fail to safe which is shift inhibit and brake stays applied..

[Venturevibesbus]

That’s what I’ve been looking for. So far I haven’t located it.

[Venturevibesbus]

The button pops out around 25psi when I bleed it and it runs all the way to 120psi and bleeds off like it should.