Classic/Antique Car Repair: powerglide transmission, modulator valve, car spray

Question
hi, sent an e-mail earlier but did not give a lot of info. my powerglide trans is shifting hard when exelerating, if i go slow it will shift more nornal, but still is a little hard.[down shifting is fine] changed the modulator valve and also checked internal valve to make sure that was not hanging up. all seems fine, plenty of vacuum. trans was working fine and one day boom. any suggestions

Answer
 Leon ;
    HI - I wonder  did  you  use  the right  size modulator
and is the vacume line going to the right place ? . and what is the color of the tranny fluid, I hope that it is
a nice clean blood  red. if  not  I would  drop the pan and change the screen/filter  and than get a can of spray == starting fluid and spray all of the parts you can get to while under the car spray the valve body ,etc. get it all clean  than re-place a new screen / filter  and replace the gasket/pan and fill it with fluid.  see if it is any better.  but is there too much vacume comming from the vacume line to the tranny modul.  ....>>><