Attached are the shop drawings used to make the spanner socket for my Allison M20 output flange nut. These may be similar or the same to the Allison MH series transmission nut, but the end user should confirm all dimensions before proceeding to production regardless of transmission type.
As per the manual the output flange spanner socket is listed as "J-9301" for the M transmission and "J-9300" for the MH transmissions in the 1978 GM Corp service manual, so these may be different tools. (If can confirm they are the same or different, reach out by DM and I will edit this resource to reflect.)
**Please note that this drawing was specifically made to create the tool for my Allison M20 output flange nut (nut model number 6700015.)
The MH output flange nut has the model number of 6771999.
**A huge thanks to Brian at Acadian Marine Transmissions for providing me the original drawing dimensions. This tool is completely based off of their shop drawings. Reach out to them for confirmation of MH compatibility.
As per the manual the output flange spanner socket is listed as "J-9301" for the M transmission and "J-9300" for the MH transmissions in the 1978 GM Corp service manual, so these may be different tools. (If can confirm they are the same or different, reach out by DM and I will edit this resource to reflect.)
**Please note that this drawing was specifically made to create the tool for my Allison M20 output flange nut (nut model number 6700015.)
The MH output flange nut has the model number of 6771999.
**A huge thanks to Brian at Acadian Marine Transmissions for providing me the original drawing dimensions. This tool is completely based off of their shop drawings. Reach out to them for confirmation of MH compatibility.
