The Stovebolt Site Forums The Shop Area Engine Shop Overdrive transmission

I have an overdrive trans that I was told came from a 55,56, or 57 Chevy passenger car. I want to put it into a 56 pick up that has a standard 3 speed trans now. The new trans looks different! The shift levers are futrher apart. So.....I'm not sure how difficult it will be to make this transition. The new trans is the same length. It looks like I will need a new speedo cable, but how do you get the linkage to work, and what other surprises am I in for?

worst case scenario... cut a hole in the floor and use a 3 speed hurst shifter. I believe you should be able to adjust your linkage to work. You may have to lengthen or shorten the rods. How does the overdrive engage? Solenoid? Cable pull?

It has both.I plan to use a dash mounted switch for the solenoid and a cable to engage/disengage.

Old School, go to Hurst site or one of the dealers that sells them. There should be a transmission identification chart on that site to let you know what your 'new' transmission is. After being told by experts that I had a Muncie or maybe a Saginaw 3spd w/OD I found out from the transmission ID page that it is a Chevy 341 (side shift plate with 4 bolts holding it on).

I went to the hurst site and it says nothing about OD transmissions on their applications information I could find, so I sent an email inquiry this evening to see if they make a shifter for a 341 trans w/ OD.

I have an old 3 spd floor shifter of unknown make that was on a chevy 3pd pickup according to the PO. I can see by holding it up to the transmission that the shift rods will not clear either the governor for the OD nor the manual lock out. I would suggest that some special install kit might be needed to make a regular 3 psd shifter work on an OD transmission.
Jerry

Use the side cover from your original 3 speed non OD transmission and it will hook up to your stock 56 linkage. The car side cover-shift arm configuration is different. If you have any problems with the installation or electrical, give me a call, I specialize in OD's, I'm in OC. Fred 562-598-9308

I have a 55 2nd series that had the 3 speed in it. I went the OD route like you are discussing. My understanding is there is a saginaw and a muncie 3 speed transmission. I had a saginaw. You have to check the side cover to check which one you have.

When I bought the transmission with the OD tail on them. It had the saginaws front. I did what Fred (rfs56trk)suggested and switched out the side covers so my linkage matched. Again, both transmissions were saginaw transmission boxes. I believe the rear section that makes it OD is muncie.

Somebody more knowledgeable will chime in.

Just an idea.

There was a running change in the 3 speeds in late '56, that is what has caused the shift plate discrepency. You can just swap the plates to make it work. Also, on the '55-'56 trucks, the shift linkage is different from the '57-'59. There is a bellcrank on the bellhousing for 2-3, so the lever on the trans is inverted form the later ones and the passenger. You also have to use the truck levers with the truck linkage.
Also-technicly, there is no such thing as a "Muncie" trans before '63, and the true Muncies are 4 speeds, not 3. There is no differnce in the 3 speeds, only the assembly plant it different. It does seem that most of the ods were made at the Muncie plant. Besides, the od unit is actually a Borg-Warner, which was used on many other brands of vehicles and transmissions, even on fords.

I got an email from oldschool56, it turns out that his OD is actually a later Saginaw so the side cover switch in this case is not an option. I think we got him headed in the right direction.
Fred

Ahh, I see. Well then that would really mess things up, wouldn't it? I take it that it's a later 7 bolt side cover, SM326 possibly? I Know that the SM 318 had the running change I mentioned. I have 2 of them-one from a '55 wagon that's in my truck now, and one from a '57 Power Pack convertible that I got for parts. The later trans has a late '56 casting/assembly dates on it. The side cover is completely diiferent from the '55 trans.

Yup, 7 bolt side cover with the small bearing retainer, probably around 66 vintage.
Fred

Fred, so how do you make the linkage work with the later 7 bolt trans? I have one and want to use it in my 59.

Tommy,
You will need to bend or modify the shifter arms on the side cover of the (new) trans to come as close as possible to replicate the configuration of the original trans. You will also need to bend the shift rods to match up with the modified shift arms. It may take a number of trips under the truck and to the vise to get it right.
Fred