The 85 intermediate plate would originally have had two dowels installed. Those dowels would have been removed when the first iron box was mated to it; the iron box clutch housing has a male ring on the front face that centers in a female groove in the intermediate plate. The aluminum box was intended to be centered by two dowels; the two that were removed for installation of the first iron box. The current box, iron, is centered by the large ring.

The intermediate plate can be loosened on the engine block, a dial indicator is then attached to the crankshaft such that it can be rotated in the large female locating groove of the intermediate plate, and the plate tapped about to achieve a concentricity of <.010".

Thank you Frank,

This is helpful. I think there is a good possibility that this lack of perfect alignment is causing my clutch problem. I don't remember removing the dowels all those years ago, but I must have done it. This also makes me think that the lack of alignment dowels and resulting, poor alignment of the aluminum 4 speed, could have been a contributing factor to its early demise. Now that I am back to an older iron box, I imagine the alignment should be better, unfortunately I put it back together before reading your post about using a dial indicator to "achieve the concentricity of <.010" The good news is that the kit I bought is lifetime warrantee. If/when it breaks I will get out the dial indicator.

Wouldn't the intermediate plate have been centered in the factory? Would the factory alignment of the intermediate plate have been different for engines mated with dowel aligned tranys vs large ring aligned tranys?

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1980 300TD with 1985 300TD Turbo motor and 240D 4 speed.

Do I understand you welded the two parts of the disc so it would not have any spring action? I think that was a mistake. It also might have created an imbalance. The springs are there for a reason, to provide a cushion against shock on the parts.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yes indeed. That, certainly had a big impact.

Looking ahead...

I think I am fighting several factors:
* Possibly poor alignment between engine and transmission
* Light 240d flywheel
* 617 that makes nearly 2x the torque of the 616

Solutions for future:
* keep an eye out for a gray market 300d flywheel
* make sure to align the trany and engine as described above next time trany is out of the car
* bought "lifetime warrantee" clutch kit, so no parts cost if/when disk fails

Thanks to all who helped out on this.
I will keep you posted.

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1980 300TD with 1985 300TD Turbo motor and 240D 4 speed.