[79 Phoenix]

Soon I will be removing the side cover and checking out my Muncie M13 HD 3 speed. Assuming all looks okay, I want to replace side cover gasket, front bearing retainer seal and rear tail shaft seal. I can't seem to find these parts, just M20, M21, M22 parts.

I can make the side cover gasket if need be.

But are the front and rear seals the same as for the 4 speeds?

[i82much]

no idea but that is super cool that you are sticking with a three speed ... thought i read somewhere that a lot of times they were actually faster than the four speeds because you don't need four gears with a big engine that pulls like a tractor and you just waste a shift with a four speed ... and this is from a die-hard four speed guy!

[Lemans64]

4spds don't use a front seal, so no they are not the same. Unless they don't use seal either.
one of the reasons they leak all the time. they use a oil slinger in front of front bearing.

[Mister Pontiac]

Originally Posted by i82much

no idea but that is super cool that you are sticking with a three speed ... thought i read somewhere that a lot of times they were actually faster than the four speeds because you don't need four gears with a big engine that pulls like a tractor and you just waste a shift with a four speed ... and this is from a die-hard four speed guy!

I'm a fan of the M-13 myself. My fav daily driving trans in my fleet.

[unruhjonny]

these guys are one of few go-to sources for 69-74 Muncie three speed "SM330" transmissions:

http://www.garagemotorsports.com/

[unruhjonny]

It is worth mentioning that some eBay sellers get the Muncie 318 & Muncie 330 mixed up;
If you're looking for gaskets, be sure that the side cover gasket is the correct one.

I believe the gasket set I got from Garage motorsports was a set cut from felpro gasket paper (not that there is anything wrong with that) - but old stock delco gaskets are out there.
One set that I bought came in an older delco style bag with the following printed on it:

G 318
3 SPEED HD MUNICE
GM PRODUCTS 1969 74

But they were absolutely the correct gaskets.

[79 Phoenix]

Originally Posted by Lemans64

4spds don't use a front seal, so no they are not the same. Unless they don't use seal either.
one of the reasons they leak all the time. they use a oil slinger in front of front bearing.

I'm going to take it apart and see if there is an O ring seal this week. Maybe it is the same as a 4 spd???

[79 Phoenix]

Originally Posted by unruhjonny

It is worth mentioning that some eBay sellers get the Muncie 318 & Muncie 330 mixed up;
If you're looking for gaskets, be sure that the side cover gasket is the correct one.

I believe the gasket set I got from Garage motorsports was a set cut from felpro gasket paper (not that there is anything wrong with that) - but old stock delco gaskets are out there.
One set that I bought came in an older delco style bag with the following printed on it:

But they were absolutely the correct gaskets.

Thanks for the link and the helpful info. This week I'm going to take the shift linkage off so I can see the side cover shape and bolt holes so I can make sure I get the right gaskets... Also do you remember if your M13 had an O ring behind front bearing retainer?

[unruhjonny]

unless I am mistaken the front seal was a Saginaw thing;
These use a front bearing retainer similar to a Muncie four speed, in that the "seal" is the bearing retainer.

There is an oil slinger at the front bearing...
Now I am wanting to go look at the front bearing retainer that I changed (from truck to car) because I don't recall there being any pressed in seal on the retainer...

[unruhjonny]

I was wrong.

We have a seal;
It actually looks as though the seal used in the saginaw transmissions is the same one we use.
Group 4.354
Pt # 39879; supersedes #3761933 (Nov 1974 printing)

This is the "truck" bearing retainer I had replaced on my "A" gear set transmission - you can see the installed seal still in place:

[79 Phoenix]

Okay thanks for checking! I didn't get to taking mine apart--maybe tomorrow. But along with the link you gave me I also found these at rock Auto... O ring looks small but side cover may match up... visually anyway.

https://www.rockauto.com/en/moreinfo...choice=0-0-1-1

[unruhjonny]

that is the wrong set.

That side cover looks to be a saginaw.

That same MPC I quoted earlier has the gasket set listed as:
Group 4.109 #3952621

Also, incase you never came across this thread before, it may be worth mentioning - HERE

[79 Phoenix]

Thanks for the link to that thread! No, I hadn't come across it. I am reaching out to the place (link) you sent me earlier and another place drivetrain.com to see if they can help with this. If need be, I can make a gasket for the side cover and I think I may have found a tail shaft seal (link below). So, althought I would like a whole gasket set, that bearing retainer o ring is all I really need (I think).

Hopefully, when I get this apart everything inside will look okay. https://www.ebay.com/itm/293080558115

[79 Phoenix]

Thanks for the link to that thread! No, I hadn't come across it. I am reaching out to the place (link) you sent me earlier and another place drivetrain.com to see if they can help with this. If need be, I can make a gasket for the side cover and I think I may have found a tail shaft seal (link below). So, althought I would like a whole gasket set, that bearing retainer o ring is all I really need (I think).

Hopefully, when I get this apart everything inside will look okay.

https://www.ebay.com/itm/293080558115

[unruhjonny]

from the same guys, here is a gasket set :

https://www.ebay.com/itm/35180797704...wAAOSwZVlXrNDU

(this actually confirms to me that the "fel pro" set I have was from them.)

Here is actually a kit that I bought from them:

https://www.ebay.com/itm/29241453283...kAAOSwXOhaYTLH

[79 Phoenix]

Thanks Jonny--Just called and ordered front o ring, side cover gasket and rear seal from The Garage. Really nice people and very knowledgeable, helpful and prices reasonable Thanks for steering me this way! Hopefully I won't need to talk to them again but I know where to go if I have issues inside. Thanks again!--Kim