Transmission Help

[71c10longbed]

After a 3 year hiatus, I am back to working on my C10. Engine (350) is being rebuilt and I am tackling the transmission rebuild. Up until today I would have sworn my life it had a Saginaw 3-speed (yeah - I know...why rebuild it).
However, now that I have it apart I think it is a Muncie. It has 36 tooth synchro gears and the reverse idler arm is different than the Saginaw videos I have been watching.

How can I confirm?

[geezer#99]

Saginaw has one bolt dead centre at the top of the side cover, Muncie has two bolts spaced about 5-6 inches apart.
Look here.

https://lugnutz65chevystepside.weebl...ission-id.html

[71c10longbed]

It is definitely a Muncie - it has the bolt pattern like you described and I ran the numbers. It came apart just like a Saginaw except the reverse idler gear - which I can't figure out how to remove.

What stinks is there are some videos of rebuilding a saginaw as well as rebuild kits. I can't find anything for the Muncie except for the earlier models. I think the one I have is a 351.

Anyone know if the 4 speed Muncie rebuild kits will work?

[geezer#99]

Can’t help you there but these guys might.



http://www.garagemotorsports.com/

[71c10longbed]

I found a rebuild kit with synchros on ebay. This thing looks extremely close to the Saginaw 3 speed. In fact the reason I questioned it is because the reverse idler gear shaft is different.

Anyone know how to get that out? There must be some sort of clip on it because I can't drive the shaft out.

Way more info on the Saginaw than this Muncie...

[zosoppp]

The HD ToTT muncie transmission should also have a drain plug on the lower front left corner.

It might be listed as a Muncie 330 or SM330. I think the 351 is just mr gasket's gasket numbering scheme.

If it makes you feel any better, I too have one of these behind my 70 C10's 350, instead of the saginaw. I discovered this only after I had bought a rebuild kit for the saginaw. D'0h!.


I have not bought anything yet for the muncie, but I have found this site:

https://www.drivetrain.com/parts-cat...d-overhaul-kit

Maybe it will help.

[zosoppp]

The year specific GM overhaul manual should have the procedure for the entire Muncie three speed disassembly and rebuild.

Here's the post with the links for the year/model specific manuals. The chassis manuals only tell how to pull/install the trans. the overhaul manuals have more info on the unit rebuilding.

http://67-72chevytrucks.com/vboard/s....php?p=5781194


the specific link for the 71 chassis overhaul manual appears to be:

http://www.mediafire.com/file/hrqizk...Truck.pdf/file

[71c10longbed]

Exactly what happened to me - I bought the Saginaw rebuild kit. Then while watching a rebuild video I started noticing some differences.

In doing some research today it appears this is a very stout transmission plus the lower first gear helps some. But very little info or parts compared to the Saginaw.

I just can't figure out how to get the reverse idler gear/shaft out....

[71c10longbed]

Originally Posted by zosoppp

The year specific GM overhaul manual should have the procedure for the entire Muncie three speed disassembly and rebuild.

Here's the post with the links for the year/model specific manuals. The chassis manuals only tell how to pull/install the trans. the overhaul manuals have more info on the unit rebuilding.

http://67-72chevytrucks.com/vboard/s....php?p=5781194


the specific link for the 71 chassis overhaul manual appears to be:

http://www.mediafire.com/file/hrqizk...Truck.pdf/file

Very helpful - thanks! The second link does have instructions and diagrams for the Muncie.

[Accelo]

Fishing here but does it have the tapered pin driven into the reverses shaft bore?
That is what the four speeds use and they often times use the same retaining system in both the three and four speeds.
They can be difficult to see especially when the case is still dirty.
It will drive from the bottom upwards.

[71c10longbed]

Originally Posted by Accelo

Fishing here but does it have the tapered pin driven into the reverses shaft bore?
That is what the four speeds use and they often times use the same retaining system in both the three and four speeds.
They can be difficult to see especially when the case is still dirty.
It will drive from the bottom upwards.

I got it out - it just needed some persuasion from the BFH. This transmisson is so close to the Saginaw it is crazy - just heavier duty.

[kwmech]

Originally Posted by 71c10longbed

I just can't figure out how to get the reverse idler gear/shaft out....

It has been a long time 20+ years, but if I remember correctly the idler shaft had to be knocked out with a long brass punch. It is pressed in from the back of the case