hopin for the best..

[jspike91]

ok, i have a 99 f550 and it will not lock into overdrive. it will go into od going down a hill, but as you roll into the throttle, the rpms start going up and the speed starts going down. just had the trans serviced and put synthetic fluid in it, but still wont shift right... should i try the silonoid pack first??? od light does not flash. in fact, i take the od off and the tc locks up fine in drive. soo.... im kinda at a loss and dont have 2g's to replace it...