I have a 1997 blazer four door. 4.3L, 4wd, 160k miles.
Replaced Parts

June 2007 - rebuilt transmission
July 2007 - water pump
Oct 2007 - steering linkage idler arm
Jan 2008 - all 4 ball joints
Feb 2008 - windshield
March 2008 - driver side door hinge pin
April 2008 - oil coolant lines (high and low side)
April 2008 - all 4 shocks
Dec 2008 - tires
Jan 2009 -MAP senor
Nov 2009 - cap, rotor, plugs
Oct 2009 - cold air intake
Jan 2010 - differential fluid
Jan 2010 - new exhaust y-pipe back
Feb 2010 - transmission filter and fluid

regular oil and filter changes


loud clunking,

This has been going on for over 6 months now and its progressively getting worse it started out just doing it once a week but now its to the point were its anytime im driving it. It seems to do it more so when the trucks warm but around 35 and anything over 40 it will simultaneously make a very audible clunk noise, and you can really feel it sitting in seat! RPM's stay the same engine is running fine. (im mostly notice this coming on the gas hard then letting off slowly or slowing on the gas then hard off the gas pedal) but sometimes it just randomly occurs even at a steady throttle. other things i feel are related to this issue. at a full stop and pushing on the pedal the truck doesn't go right away it takes a half a second. some times when your at 25% throttle and trying to get up to speed the truck feels like it has a centrifugal clutch ( like you hear and feel the engine winning up then slowly increasing its power to the ground ) then going up long steep hills it sometimes doesn't drop it self down a gear instead it will use the current gear its in and somewhat struggle up it while faintly jerking bit.

i really feel like this is more of a transmission or converter rated issues
but im not sure