<VV> PG Question

[Geoff Johnson]

Working on a PG.  Unknown year of powerglide, engine is a 110.   When 
shifted into drive it engages really hard.  Makes a big shudder and slams 
the car hard.  Almost feels like shifting into drive with engine revved 
high.  Idle is at a good speed though. It only does this about 2/3 of the 
time when shifting into gear.  Also when it does this it shudders as it is 
shifted from drive to low.  Upshifts and downshifts just fine while running 
down the road, shifts are very smooth.  I tested for broken e-clip 
according to test described in Bob's book, adjusted the low band and 
changed fluid, fluid is at correct level.   Ideas?  Surely something I am, 
overlooking.  Is it throttle valve adjustment or something  else to look at?
Thanks
-Geoff Johnson