How to free up my 440

Had a two ton truck years ago with a stuck motor. Put small amount of diesel in each cylinder let it soak a couple hours. Pulled with another vehicle on graveled road . With it in 2-3rd gear popped the clutch a few times . First few times the drive wheels just slid. Then it broke loose and ran for years. If yours is an automatic a different approach is needed. MMO mentioned above may be a better additive.
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