Allison link .... http://www.allisontransmission.com/publ ... onType=All
goto bus series under vocational at bottom of page... click on bus series
Item 1 is for the ALLISON 500 SERIES ........LINK http://www.allisontransmission.com/site ... +modulator
Before you order any parts get the serial number and double ck all your carburetor vacuum lines...
The modulator should only be used after appropriate troubleshooting has been completed,
such as verifying that the carburetor is performing properly, vacuum lines are in good
condition (no leaks or splits), etc.
The new kit, P/N 29501199, is purple in color and can be purchased through the ATD
http://www.allisontransmission.com/serv ... wnloadID=9