[steve's 69ss]

Hey peep's. I have either a muncie m21, Or a m22 Four speed in my 69. I cant seem to find a drain plug on it. I see the fill plug up about half way up the side of the case.

[parkbrau]

What do you want to do Steve? Drain? Remove tranny? Change lube?

To drain or change you'll need one of those hand pumps and pump it out, If you take it out get some cat litter and one of those plugs that will plug the out put shaft. Then drain it while it's out.

[steve's 69ss]

I would really like to just drain it and get some fresh gear lube in.

[deerhunter]

You either have to pull the transmission and dump it or use a suction gun and pull as much as you can. Another bad design we all have to live with.

[zdld17]

It may be possible to pull the lower center case bolt, between housings, and allow to drain over night. I understand its very slow but can sometimes be done. You could also take it to a oil change place, they have these suction pumps with long flex tubing, that the use to drain rear ends with. Sorta like a vacumn pump set up.

I believe the M22 is the only one that has a drain plug.

[SEK Z28]

Don is right, only the M-22 got a drain plug from the factory. Why is this?

One other option is to drill and tap the drain boss for the drain plug. I did this when my M-21 was out of the car during the restoration. Trust me...the magnetized drain plug (still available from GM) is a nice addition and I can change fluids without getting 1/2 of it on the floor or in my hair! The full head of gear oil should help evacuate the drill/tap shavings and you can flush the gearbox through the fill hole. Yes it would messy; but only once. But...I'm not sure there is enough room to do this with the transmission in the car. If there's not enough room for the tapping operation, the suction gun works well. With over 275,000 miles on my M-21 before the rebuild, I can't count how many times I was under there with a suction gun.