mine had the laughing monkey syndrome as well as wear on the gear. have seen others have the same bushing seizure and resulting noise. are you sure the bushings are exactly the same? I was under the impression that as the bushing seizes the gear becomes harder to turn and that's when the wear starts to happen
No the bushing wear is secondary to the gear wear. Anyone that has the "laughing money" syndrome/bushing failure already had well progressed gear wear.
What happens is the gear on the CPS assembly starts to wear because it was not properly hardened when it was manufactured. As a result it starts to wear quickly and as it does it opens up the gaps between its teeth which is where the camshaft gear meshes in.
Now you have the camshaft gear putting a lateral (sideways) load on the CPS shaft because of the higher clearance between their gears.
Once this type of wear starts it exponentially speeds up because as the more wear occurs the harder the gears are beating on each other which in turns makes more wear and so on.
Think of a rear axle with too little pinion depth. The pinion ends up acting like a hammer beating back and forth on the ring gear instead of staying constantly engaged with the ring gear. At the same time since the ring gear isn't fully engaging the pinion its trying to rip the tips of the teeth off the pinion.
We just don't see bearing failure much in the pinion of a real axle because its much more robust than the bushing system we see in the CPS assembly.
But the CPS assembly wasn't designed nor does it need a very robust bushing in it if its kept within the specified tolerances.
But as I said earlier I pulled both a 99-04 CPS assembly and my original 04-06 CPS assembly and compared them. I cannot see any difference in shaft support bushings, the shaft itself nor the 3 oil passages at bottom of the housing which allows oil to work its way on top of the bushing.
The 04-06 and pre-06 CPS assembly and pre-99 distributor cap assemblies operating under design conditions in a very low lateral load design. The "splasher" type oiling system they all use is more than sufficient to lubricate the shaft and bushing under such low lateral load conditions.
The lack of any visible wear or measurable play/runout or lack of smoothness in rotation of the shaft or bushing from my old CPS assembly would seem to support this assertion also.
On a side note I think that the huge (almost 50%) reduction of ZDDP in motor oils isn't helping with wear on surfaces like the metal on metal of the bushing/shaft in our CPS assemblies. There was a reason that ZDDP was put in oils, yes new motor technology doesn't need it, but then again the 4.0 isn't a new technology motor is it?
But all this is just my educated opinion, after all I'm just a medically retired police officer turned high school science teacher so I'm by no means an engineer nor do I claim to be one nor did I stay in Holiday Inn Express last night.