cought between clonks !!!

Hi , i need some help, i've posted the same mesage 2 months ago and the only answer i got was "ask dale" so dale feel free to coment ( please) . my gc 93 5.2 now has 99.k miles ( last time i posted had 93.k m. went to Manhathan and back plus some normal use ) and this is the problem :
accelerating the car goes fine ( may lack some power ) but when breaking from 20 mph to 15 it downshift with a clonk !! and at the same moment the rpms jump to 1000 , same times it dosn"t hapens but most of the time that is the way it work so i have to take my foot from the brake at the wright moment , say 16 mph , so the clonk !! is not so loud , this is realy anoying during rush hour , if you accelerete realy slowly you get a clonk !! too :banghead:CLONK !! . please help .

It could be your u/joint`s I would have them checked first.If they have never been replaced they are due.

Try checking your engine and transmission mounts. The touque from the transmission when it downshifts can cause everything to shift and bang against something.