Everything I had read led me to understand there is no drain plug on the M20 in a 68 GTO, the old oil has to be pumped out through the fill plug on the side...HOWEVER! My 68 Pontiac Service Manual tells me on page 7D-7 to "Remove drain plug at bottom of transmission and drain lubricant"...so, this led me to examine the "bottom of transmission" in search of this drain plug. I do not see one, so I expect maybe some of the Muncie's had the drain plug and some didn't? Maybe I am not looking in the correct place? I have not yet been able to budge the fill plug so won't be draining anything (either through the drain plug or the fill plug) until this issue is solved. Should I be seeing a drain plug? Thanks as always for guidance.