Well I finally found the cause of the clutch failure to completely disengage on my 300TD wagon which I had posted about a couple of months ago.
I finally had a friend drop the tranny and examine the clutch. The cause was that several of the fingers on the pressure plate were bent slightly apparently causing the plate to disengage unevenly and incompletely.
The new part (from a sachs kit) has a new pressure plate design where a ring is attached to the end of the fingers which reinforces them and prevents them from breaking off or bending so it looks like it is an improvement to the original part's design. The release bearing contacts the ring rather than hitting the fingers. What's funny is the old clutch looks to be OEM while the new kit was aftermarket but appears to be an improved design. We put the new clutch disc, pressure plate, release bearing and pilot bearing in yesterday and test drove it to find it is all fixed.
Now I am able to use all 4 gears and reverse again