Muncie M20, M21, M22 Fill and Drain Plugs Markings

[Ken K.]

Does anyone know what the fill plug should look like on the Muncie trannys? Are there any makings, letters, or symbols stamped into the plug. Do the "Drain" plugs on the M22 have the same makings? Does anyone have a good photo of a original plug? (Fill and/or Drain)

[Joe L.]

Re: Muncie M20, M21, M22 Fill and Drain Plugs Mark

ken-----

Many original drain and fill plugs used for M-22 transmissions were equipped with an integral magnet. Many of these had the word "Lisle", the manufacturer, embossed on the head. Otherwise, the non-magnetic type plugs used on all other Muncie variants had various letter codes denoting the manufacturer or no coding, at all. I don't think that there was any particular style which was used exclusively or, even, predominated.

[Warren F.]

Re: Muncie M20, M21, M22 Fill and Drain Plugs Mark

Ken:

My M22 trans in my '71 LS-6 has the letter P stamped into both drain plugs.

[Wayne M.]

My OTC P1D16C has Lisle for both

Can email you a detailed pic of both lettered and magnet ends.