Recently purchased 1959 3100, 3 speed transmission has synchronized first gear, 7 bolt side cover. I have attached pictures of casting numbers. I think it is a post 1966 trans but have no idea on Muncie designation. Any help would be appreciated. Thanks, Ron Greene
Hy SWODA, welcome, I believe that is a Muncie 319, there is a similar looking Saginaw full syncro three speed, but I believe yours is the Muncie, hope that helps.
A Muncie 319 is a 318 with a Borg Warner overdrive grafted onto it. It has a 4 bolt side cover and the parts ahead of the output shaft interchange with the non-overdrive 318. What you have there is a Saginaw that has had the shift linkage cobbled up to fit in place of a SM-318. The driveshaft is at least an inch too short. It looks like Mr. Bad Pliers has been working on your truck! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jerry, Thanks, I guess I will be looking for a SM-318 and the shift linkage. I thought the yoke looked a little too far out. Other than the trans the truck is all original. Ron Greene
If you're planning to be in middle Tennessee anytime, let me know- - -we might be able to do a little horsetrading. I've probably got more use for a Saginaw than a 318.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
The Saganaw transmission that is currently in your truck is a full syncro unit. The original SM318 does not have a syncro first gear so it would be a step down if this one shifts and drives OK, just straighten up the issues and drive it. Fred
1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes 1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes 2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans 1947 Willys CJ2A w/F-Head engine
Fred Thanks for the advice, if you shift normally or quickly into third gear it seems like the synchro is not doing its job and you get a little crunching. Shifting very slowly it is OK. I located this trans, appears to be a 1955, gear ratios are correct 2.94:1, 1.68:1 and 1:1 Is it the correct 318? Are the shift arms correct for a 3100? Ron Greene
After more research the bottom bolt holes are not threaded, which means it is for a car. My understanding is you use longer bolts and add a nut. It appears that is how the Saginaw is now currently mounted. Is that correct? Ron Greene
Saginaw 3-Spd 1970 - 1972 3925647 Main case 3873886 Tail housing 3952645 Side cover
No overdrive because there is no solenoid.
Yes on the holes. Fully synchronized. Grooves on input shaft for gear ratios.
Crunching between gears can be a lot of things. Open it open and look for gear wear. Check for worn synchros. Check cover plate bushings (shaft to plate) for wear.
From my humble experience and opinion: Throw column shift in the trash and buy a good Hurst Mastershift (not Myster shifter).
Last edited by buoymaker; 02/25/202210:22 PM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Ron, That 55 transmission is from a car. The main difference is the clock positions and the shift arms on the side cover. You would need the truck side cover to use that trans. As stated, longer bolts with nuts are commonly used to mount a car trans to a truck bellhousing. The linkage rods on your truck are correct, just cobbled up to be able to use the Saganaw. It's possible to use the Saganaw in your truck, and many on this site have done it. It is a better more modern trans. It may only need some adjustment and tweeking for it to work well. Fred
1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes 1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes 2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans 1947 Willys CJ2A w/F-Head engine
I have a 69 Saginaw from a C-10 truck. I had to make custom everything for it to work but it's a great transmission. I had a non syncro 318 which I pulled. I set the 318 on the curb, and literally gave it to the first person that drove by.
I made dies at work to stamp the holes in the shift arms after determining the correct length. A double bell crack was developed to still use the column shift.
The blue background pic is a mock up that shows the layout.
Also, my Muncie 318 and Saginaw were there same length. Around 21.250".
Saginaw 3 and 4 speeds did not have a short tail shaft option like the 58-64 Muncies.
bouymaker, Thanks for the breakdown on my transmission. Will open it up and take a look.
Fred, I think I will keep the Saginaw as you and others have suggested. Do you or anyone else have a picture of the original 318 sidecover with the clocking position of the shift arms shown?
NeptuneGreen55, Nice work with that double bell crank, I am seeing an Airframe & Powerplant mechanic with the bell cranks and safety wiring. I measured the Saginaw and Muncie 318 and came out with the same measurement,
HotRod Lincoln mentioned my driveshaft looked an inch to short, do you guys agree? With the trans being the same length I would assume the original driveshaft was used with a different spline
buoymaker, Thanks for the page from the factory assembly manual, I now have an assembly manual. So if I look at Section 7 Sheet 4.01in the Factory Assembly Manual correctly the 3100 has a shaft off the bell housing with a bell crank for second and third gear, my set-up does not have this, instead it has two rods from the shift mechanism on the steering column that go in one piece all the way to the cobbled up shift arms on the transmission. My Sheet 2.00 does not look like yours. If someone has pictures of the stock linkage on a 3100 it would sure help. Thanks, Ron Greene
Ron I find myself making errors all the time. The drawing I sent you is not correct because it's for 1947-55 1st. I went back and looked at your profile and realized that I should have sent one for 1959. You have the correct book now anyway.
The shifting system design with less moving parts, less pivoting points, shorter shift rods work better for me. Column shift works okay if treated gently. A little bit of wear and it becomes sloppy shifting.
Last edited by buoymaker; 03/07/20225:54 PM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
