Clunking Sound In Transmission

[nascar]

I have an 87 GN and a 88 LeSabre T-Type. In both cars, when going from either PARK or NEUTRUAL to any other gear, I get a "clunk" sound. It seems to be from "slack" either in the trans or rear end. The :eSabre is front wheel drive. I know this is a common thing with higher mileage cars but exactly what is it. Any help would be appreciated. It is very annoying.

 

[chris718]

usually it is accumulated clearance in the drive shafts u joints or drive axle cv joints ,or worn spider or other final drive gears .adjust idle and tv pressure to their lowest possible settings for increased cushioning of drive gear engagement.