'87 5ktqw driveline backlash?

[Rod Michaelson <HOTROD@pacbell.net>]

Morning,
Not sure if I have a problem or not on a '87 5kcstqw with 226K miles.
In second and first when slowing down the car jurks to a slow. You have 
to push clutch in to stop the jurking. Engine runs fine it is all in the 
driveline/transmission. Bought the car 3 months ago and noticed it 
somewhat, now my daughter has driven it a month and when I drove it last 
weekend noticed it was happening more often. Any imput on where to look.
Noted transmission output shaft seal is weeping.
thanks,
Rod Michaelson
'95 90csq
'91 90cs
'87 5kcstqw
'98 chevy k1500