Air throttle and no reverse?

[JackConrad]

Just got a phone call from a busnut that said he installed an air throttle and air modulator on his MC-8 with 740 auto. Started the bus and everything worked as normal, UNTIL he put the bus in reverse=No Reverse. I told him to first confirm the transmission is actually shifting into reverse (mechanical shift linkage).  Any otrher suggeestions?  Jack

[mikelutestanski]

Hello:     This may not bear on the problem but may affect shifting...    The air line from the pedal splits when near the transmission. One line goes to the modulator and one line goes to the throttle actuator..   Make sure the airlines are the same length from the tee to each piece  (the modulator and the throttle air cylinder).    This is important so that the air signals arrive at the same time to allow the modulator to work correctly.   I do not know where the info came from; but it helped me when I set the air throttle on my coach.  I may have received the info from the guy that I purchased it from.. He put in a series 60 and had no further need of that system. 
     FWIW.     happy bussin    Mike

[JackConrad]

I asked him about the length of the lines from the TEE when I talked to him. He dais they were cut exactly the same length.  Jack

[ChuckMC8]

Jack, I'd ask him if his neutral saftey switch works properly......if it does, tell him without the engine running, place the selector in reverse. If it starts, his shifter mechanisim isn't moving the trans into gear.
If it does crank (and doesnt go backward) I'd suggest he reverse his steps with the modulator untill reverse is restored.....but I dont know of any effect that the air modulator would have on his problem.
       His shifter probably needs to be adjusted...HTH Chuck