It is not necessary to disassemble the rear housing to replace the seal on the R10H series overdrive. Some other OEM's yes.
To replace the seal on the OD shifter shaft: Remove the cable and move it out of the way, there is a small hole on the lower part of the block that holds the shaft, there is a tapered pin in that hole. Use a small pin punch to drive the tapered pin upwards, remove the pin. The shaft can now be removed.
The seal part number is: 6130, Seal, shift lever OD. You should be able to order the seal from Napa or a bearing supplier in your area.
Reassemble in the reverse order.
Fred

Note: Many of the publications are generic and cover a wide range of overdrive units. If the publication was published before 1955 it likely doesn't show the Muncie/R10 unit.


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