M4A2 Sherman clutch shim question

[Malcolm Towrie]

We’ve got the two 6-71 Detroit’s out of the Sherman for resealing due to oil leaks.
Both clutches have shims between the housing and flywheel. Hopefully the sketch shows the location and the other photo shows a shim.

One clutch had one shim per bolt, the other clutch had two. The shims are 0.032” thick.

Cleaning up the heat checking involved removing a total of 0.020” from the flywheel and pressure plates, ie 0.012” from one and 0.008” from the other.

The only manual I can find that mentions these shims is for the M36, which uses the hull of the late M4 A2 HVSS. All it says is when friction disk gets down to 0.370” thick, remove the shims. Our friction disks are 0.455” and 0.425” thick so well above this minimum spec.
Trouble is I lost track of which clutch is which when we got then surfaced. Anyone have any info of how the OEM determined these shim thickness?

Thanks,
Malcolm

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