V730 Transmission--Hard Shift

[Roger4106]

My V730 shifts very hard, upshift is not bad.  Down shift is very hard under full power.  Starts from stop 1st gear smooth shift to 2nd at about 48 to 50 mph.  Shifts to 3rd and lock up at almost the same time.  Same on down shift.  Lockup to 3rd very hard under full power, even 1/2 power.  2nd to 1st down very smooth.    Took valve body to a good Allison shop, best in Iowa??     They put valve body on test stand and messed with those adjustable springs on the back of the valve body.   When they got done it was no different.  I have been shifting manually as feels like it may tear out the drive line.  Seems like that to separate lock to 3rd gear by 4-5 mph would solve the problem.  Any one have some ideas?   Roger 4106

[TomC]

Make sure you're throttle modulator is adjusted correctly. If it is in the full throttle position, it will shift hard all the time. Can you get lower RPM shifts with partial throttle between 1st and 2nd? 2nd to 3rd shift is typically a speed related shift only. My V730 uses an air modulator running off the air throttle. If you have a cable throttle, make sure your throttle modulator is hooked up. Typically the shifts should be 1st converter to 2nd converter, then 2nd converter to 2nd lockup, then 2nd lockup to 3rd lockup. You should be able to get 1st gear lockup if you pull the gear shift to 1st. Then you can climb long hills (around 32-35mph) in 1st lockup and save a bunch of heat. Good Luck, TomC

[luvrbus]

It is a modulator problem is the pin there ? 3 types of modulators used which do have the electric,air or cable