MELVIN

Im usually really picky on maintainance, but kept putting off changing out my 4 speed gear oil until today because there is no drain plug, just a fill plug: You must get under the car, suction pump the old out, and refill the reverse. I finally quit putting it off and got a hand operated pump today, and here is what I found

I only got about 1/2 a qt out. I thought maybe it was because I just couldnt get the suction hose in the right area inside the case from the filler plug, as you have to kind of move the hose around to get around the internal parts to get at all the fluid. But still, I only got about a 1/2 qt total
sucked out

So I went to pump in new stuff, and got a full 2 qts in before it started to dribble out (the proper fill)

point is, dont wait so long to check your manual tranny fluid. Its not hard to get to, its just you have to get your car up on jacks, remove the plug, get some sort of pump, and go from there. I couldnt beleive I let it go for so long, so low

By the way, what is the total fluid capacity for a 4 speed? Neither the factory repair manual or Haynes states the total capacity for a 4 speed. Just that you fill until it dribbles out the fill hole

At the same time I changed the rear end oil. Same drill, but this time got about 2-1/2qts out. Placed in 4 ounces of posi additive, and got in just about 2 1/2 qts of new rear end oil

Stingray1970

I just looked in a 76 owners' manual and it says a four speed holds 3.0 pints

LAvetteman

Hmmmm, I thought my rear only used 1.5 quarts, plus posi addit.

MELVIN

Sorry, my bad on the rear end. It only took 4ozs of additive and two, 23 oz bottles of GM rear end oil (just checked the trash)

But the tranny took a full 2-1/2 qts after pumping it as dry as I could before it started to dribble out

Fevre

I tried to put in 3 quarts, not reading the capacity very carefully, but only got about 1 1/2 quarts in before it came running out all over the garage floor. :(

Tom454

Hey John...

Me & Mark just rebuilt his Muncie and we filled it before we re-installed it in the car....

The manual said 3 pints, and that is all we could get in before it started to come out the fill plug. We had it sitting on the kitchen table... we poured the oil in through the side cover (since it was still off), and when we levelled it correctly, the oil was right at the plug threads... just starting to dribble out. We left it at 3 pints, which seemed to be correct.

FYI

Tom

drspeedy

:lol: :lol: There must not be a Mrs. Mark!! :lol:

Marks69BB

drspeedy Good call! But a lucky one; it was Tom's kitchen table! :lol: If you saw his garage at the moment you'd know why!

Constantly on the lookout for a new honey tho. (not ready for another Mrs. Mark just yet! :jester) Unlike the ex, she has to like vettes and put up with my infatuation with them.

Fevre

Me too. She also has to put up with my inflatulation in them. :jester

Cali,68,L-79

What kind of tranny you have? I have both fill and drain I remove the drain plug and let it drain out Then with fresh 80/90 and a hand pump and 4' hose pump it throughout the tranny with the drain plug still off till all I get is nice clean oil. Then put on the drain and fill it up to the lower edge of the fill plug (just barely dribbling out)

MELVIN

4 SPEED, M22

Cali,68,L-79

Then what the hell do I have??? Saginaw?

73 LS-4

My M-21 has drain and fill plugs, what year is your tranny? maybe the early muncies didn't have drain plugs.

:cheers:
Pat Kunz

Stingray1970

I think you have a sixth design ( 1974-1988 ) Super T-10.

PRNDL

From a corvettemagazine.com article by Alan Colvin:

" For the 1970 model year, there were two major changes to the Muncie four-speed. In previous years only the M22 transmission had a drain plug, however, beginning in 1970 all Muncie four-speeds now had a drain plug."

I do not have a drain plug on my 68 M20. John, You dont mean M22 "rock crusher" do you? You actually would have a drain plug if it was an M22, but more common M21 or M20 for 68 had the place for the drainplug, but none drilled. MJ

MELVIN

Fellas,

My "drain" and filler are the same hole. On the side, passenger side of tranny, about 1/2 way up the tranny body

My main point was this: Just make sure you have enough fluid. Mine was low as hell after putting it off for so long.

Cali,68,L-79

Anything on the tranny case to verify?? Car is all original so want to know what kind of tranny I have.

Larry B.

My original late 69 M-20 has a drain plug.