Thanks Greg
Well I will stay confused if there is not some chronic problem on the pto side. The cases have casting date codes on them of 81, 82, and 83....my original 3400 dead case is the only 84 date code. Though I can't yet visually detect any difference that might differentiate early/late.
2 of the 5 have minimally perceptible main bearing play, one more is even worse, but not even close to how bad my original 3400 saw was.
Dave,
I couldn't tell ya what year they changed a few things on them, and they are small. Basically, just added webbing, etc. in the castings. Especially around the rear counter-vibe mounts, for the rear handle. Some added to the interior of the cases also. The early ones I have seen, had a different style oil cap, for the bar oil tank.
Gregg,