That's a real bummer Dude!!! <img src="/forums/images/graemlins/angry.gif" alt="" />

I'm wondering if you have an auto tranny, if so, you may have a cracked flex plate which is causing the knocking. Especially considering the old motor had the same noise. A cracked flex plate can sound just like rod knock.

One way to diagnose a knocking rod is to undo plug wires one at a time and when you kill spark on the offending cylinder, the knocking should go away.

How's your oil pressure, does it come right up and stick around 50 psig+, or is it slow to rise and a low value??

What's the supposed history of this motor and what did it look like inside when you had the oil pan and intake pulled? My 3.4 was spotless inside and that made me very happy!

I'm thinking (as terrible the thought may be) that it's probably easier to pull the motor back out. Don't think you'd have much fun at all trying to drop the entire front suspension for access to the oil pan.

One thing that I found made it easier was undoing the (4) very large bolts (2 per side) that hold the diff/axle assy to the frame. This allows the assy to drop down a bit and makes more room for the oil pan to clear. Also, removing the motor mounts altogether gives you more room to move the motor around.

I'm curious, did you do a Post-Mortem on the 2.8; did the main or rod bearings show signs of great distress? When I tore apart the <just-starting-to-knock> 2.8 in my '89 "stroker project" Trooper, the rod bearings were pretty wiped and the rear/thrust mn brgs were totalled. This one had deteriorated intake manifold gaskets and antifreeze in the coolant, guaranteed to eat up bearings!

HTH, keep us posted..........ed