Allison 3000 problems

[Jwlt500r]

I have a 2002 international 3800 t444 with Allison 3000
I’ve owned it for about 8 months. Basically setting in my yard. I go out and start it every few weeks. I tired to move it the other day and the engine just revs up and it tries to move But won’t, I assume the transmission is just slipping. Please tell me there’s a simple fix. 🤞🏼🤞🏼🤞🏼Thx

[dmattarn]

Have you checked the fluid level?

[AzironaZack]

Have you released the brakes?

[Native]

Has the air pressure built up to operating pressure?

[Johnny Mullet]

Start bus and let air pressure build to 100+ psi. Release the parking brake and try again.

[stlthe]

make sure all your emergency exits and doors are closed. my bus wont move until those conditions are met. it made for an embarrasing few minutes the first time i went to a truck-stop to fill up. the emergency door was latched, but not QUITE enough. after i did a walk around I reclosed the latch and off i went.