3 Speed transmission (3 on the tree)

[GreenBay1921]

I have a 1968 swb with a Muncie 3 speed. The truck had been sitting for 25 years before I got it. It shifted fine, but was roar like a beast. When I drained the transmission, it had a good 10-12 oz. of crystal clear water in it. When I cracked it open it has a good bit of pitting on the tip of the main shaft & most of the gears. That being said, I'm pretty sure I need to scrap it. I'm looking to keep the 3 on the tree, so I've been looking for a replacement. My question is: will a Saginaw work, & if so, will I need to replace shift linkage. It looks like the linkage where it connect to the transmission is different from the Muncie to the Saginaw. Do you guys have any suggestions about my situation? Thanks guys.

[EARNHARDT#3]

Not sure about the linkage. The Saginaw is a little longer so you'll need to either have your driveshaft shortened or buy another one.

[GreenBay1921]

Originally Posted by EARNHARDT#3

Not sure about the linkage. The Saginaw is a little longer so you'll need to either have your driveshaft shortened or buy another one.

Will a Saginaw that was in a lwb work on my swb if I get a new driveshaft?

[EARNHARDT#3]

Originally Posted by GreenBay1921

Will a Saginaw that was in a lwb work on my swb if I get a new driveshaft?

Yes. Again I don't know about shifter linkage though. My local shop charges $70 to shorten and balance a driveshaft.

[firedemon]

i don't know if mine is a Saginaw or Muncie do you have a couple pics of yours I have the stock linkage from mine your welcome to . mine is a 67 long bed l6 I converted to floor

[GreenBay1921]

Originally Posted by firedemon

i don't know if mine is a Saginaw or Muncie do you have a couple pics of yours I have the stock linkage from mine your welcome to . mine is a 67 long bed l6 I converted to floor

[midniteblues]

The Muncie and sag linkages are different
The Muncie is a shorter trans there for the linkages are shorter
There isn't a big differnce. You just might be able to get it to work.
I know this cause when I did my 4ott I had 3 sets of linkages and one set was from my 67muncie. And I grabbed two sets of sag from a jy.
But I also use a mismatch set of shifter levers to make it work rite.
Oh an your slip yoke is gonna be different the Muncie had a different spline in the yoke.
O
And of course the driveshaft

[dell72]

Not to hijack the thread but I have a few questions.How would a person identify the muncie from the saginaw? Is one stronger or preferred over the other? I have a 69 C-10 that is all stock with an I-6 3OTT.

[EARNHARDT#3]

Originally Posted by midniteblues

The Muncie and sag linkages are different
The Muncie is a shorter trans there for the linkages are shorter
There isn't a big differnce. You just might be able to get it to work.
I know this cause when I did my 4ott I had 3 sets of linkages and one set was from my 67muncie. And I grabbed two sets of sag from a jy.
But I also use a mismatch set of shifter levers to make it work rite.
Oh an your slip yoke is gonna be different the Muncie had a different spline in the yoke.
O
And of course the driveshaft

I've heard the later SM318's had a 27 spline output instead of 16. Is that true?

[firedemon]

these are the ones that came off mine look different from what you have

[midniteblues]

Originally Posted by EARNHARDT#3

I've heard the later SM318's had a 27 spline output instead of 16. Is that true?

I can't remember off the top of my head. I would have too dig my Muncie out of the shed too check it out.

Op, if I were you I would flush that trans an run it till it gives up the ghost.
Most of the 3spds I've ever driven did have a considerable amount of rumble to them.
But it could be a dry /wore out pilot bushing or toasted
Front bearing. Also the throw out bearing can make a good rumble too.

Here's one I'm not sure of either the 67 bell has the smaller bore I don't recall if the
Sag 3spds has a small or large bearing retainer

[EARNHARDT#3]

Originally Posted by midniteblues

I can't remember off the top of my head. I would have too dig my Muncie out of the shed too check it out.

If you could please eyeball it and let me know. You shouldn't have to count the splines because the 16 spline is much more coarse than 27.

[midniteblues]

I'm new too this phone thing so I hope this works.
Here's a pic of the disc,trans and output from my Muncie 3 spd Looks like a 10 spline.

[67chevemall]

Clean it the best you can and use royal purple juice. Run it until it self destructs. It could be years and years before that old girl gives up.
Can't beat the Muncie.