B500 Allison Shifting

[Glennman]

I wrote in my bus project board about the shifting of my bus when going down hill. I don't know what normal is as I don't have a lot of experience with these transmissions. When flying down a long grade doing about 75 mph (this was sort of a test run), I looked over at the electronic shifter and it read 4th gear. Just to see what would happen, I attempted to hit the up arrow to see if it would go into 5th or 6th gears. It stayed in 4th until I reached the bottom of the hill and started to level out. While everything ran out fine the best I could tell, I am wondering if it is downshifting automatically in order to control the speed on the hill (?)  Is that the normal operation of a B500? I don't believe I have the Retarder version. Thanks all!

[luvrbus]

My 4060 Allision shifted to 4th when the Jakes were turned on

[Van]

Download the manual here
https://assets.wellertruck.com/reference-materials/owners-manuals/fourthgenshift-selector-manual.pdf

[buswarrior]

Yeah, many, many of the MCI were programmed to ram down into 4th when the jakes or retarder were calling. For many/most situations, way too much...

Damned annoying.

The same vintage Prevost did not, you could drag full jakes in 6th, if that's what you wanted to do. Didn't do much, but the point is, the driver was making all the decisions, right or wrong, not the machine.

Never got a straight answer from a reputable source...

Happy coaching!
Buswarrior

[luvrbus]

They are easy to change with the Allision software ,I had my 4060 programmed for the Jakes to work in all 6 gears dropping to 4th bugged the hell out of me too

[Glennman]

Thank you everyone for the replies and the links. I'll be looking into those things for sure. I wish I had Jake Brakes and the Retarder feature (at least Jakes anyway). Adding Jakes may be in the future. I didn't mind the way it went into 4th, as long as I know it's normal. The hill I was going down was pretty long, but not as steep as some of the mountains in the area. I plan to take it over White Pass (here in Washington State, Hwy.12) in the spring. That has a pretty good slope, is windy and even has a runaway truck ramp at one point (heading west). I've driven my other buses over it and it definitely puts the bus (and the driver) to the test. That will give me a better idea on how the bus handles.