The transfer valve is staked into place and it is steel into alloy which is always problematic. ¹⁾
If you do remove/replace the valve, make sure it is staked back in place when you finish. Use some Loctite on the threads also.

• You can use a hammer and punch to stake mark out of the valve slot. Be careful when hammering on your cases. ²⁾
• You can find a socket that same size as the OD of the valve. ³⁾ Lay it on the valve & give it some face hammer shots. Again, be careful.
  Or get 2 hammers, 2 drifts, 2 guys, one for each slot. Get in rhythm so both hit at same time.
  You don't want to brutal. It will break loose if you repeat 2&3. Be careful not to mash the valve into the case. That would re-stake the valve. Again, be careful.
• You can use a Snap-On Drag Link socket to remove the transfer valve. ⁴⁾ You may have to grind it to fit the slots in the oil transfer valve. ⁵⁾
  However Snap-On has a 15/16“ wide version, stock # A17A, that fits quite well with no grinding needed. ⁶⁾

Special tool to remove / install transfer valve. 7)