Shoe Box OD Transmission

[Shoebox]

I installed an overdrive trans in my 51 Tudor, and boy it made that car even more fun to drive. Well, I don't have THAT shoebox anymore, but will be looking at a 50 soon. Question, was the same 3 speed with OD used in 49-53 or even longer? I ask because I may begin the search soon. Thanks guys.

[Ken Henry]

The side cover is different on the 51 from 49/50, and the mount is in a different spot. But I’m running a 49/50 OD trans in my 51. Just needed to swap the side cover (for clutch mounting), reverse the mount, and use a spacer as I recall. Ken

[tubman]

Since no one has jumped in here, I will add a couple of things that I know. First, because of the introduction of the Fordomatic transmission in 1951, the location of the rear mount was changed from '50 to '51. I believe that it was moved forward, in '51, but can never seem to remember which it was. I have a couple of examples of each at my shop and had to tag which is which to help my memory. Also, sometime in the mid '50's ford went to the Borg Warner T85 transmission. While still a three speed, it is quite a bit stronger than the earlier Ford transmissions (they were used behind some of the early FE engines). They also came with the R11 overdrive rather than the R10 units used on the earlier transmissions. The R11 is also quite a bit stronger that the earlier R10's. All in all the T85/R11 is a pretty robust unit. The front bolt pattern through 1964 is the same as the earlier Ford transmissions, and although I have never done it, I believe one could be substituted for the earlier unit, resulting in a virtually indestructible combination behind a flathead.

Ken, I just saw your post and didn't they change with the side cover (the clutch mount) take place with the introduction of the swing pedals in '52? I believe all of the "shoeboxes" ('49-'51) used the same clutch activation system.

[Mac VP]

The rear support mounting flange moved forward for 1951 and the spacing for the two bolt holes opened up a bit to an even 6” center to center. The overall length of the 49-51 transmissions remained the same. The boss on the side cover (for the clutch release mounting bracket) changed slightly.

The gears in the 3 speed portion of the transmission changed completely beginning with the 1951 type. Assuming you swapped out the entire gearset, one could put the 51 gears into the 49-50 transmission if you wanted to.

[Ken Henry]

Right, I believe the boss one the 51 side cover is lower and doesnt line up. But side covers interchange easily enough and are not specific to std/OD transmissions

[Frank Miller]

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49 qnd 50 interchange and can easily be spotted by the reverse lockout switch located behind the lever at the top of the transmission. It was discontinued on the later transmissions and Ford said to bypass it if it failed as it was never really needed.
With a little luck you should be able to find exactly what you need.

[rotorwrench]

Ford considered the lock out switch redundant so the new 1951 transmission didn't have it. There may be some early 1951 Fords that had the earlier type but I don't know with any certainty. The Mercury cars for 1951 used up the early types before change over in or around February of 1951.

I like having the lock out switch when running with the transmission locked out for long periods like driving in mountainous terrain or pulling a trailer. This way the OD solenoid isn't on all the time during this type of operation. When I was a kid My Pop and older brother pulled trailers with our 51 Merc quite a bit. We used all the vehicles on the farm, including the family car.

[Newc]

I once was told that the X member frame of the '51 converts necessitated the rotation of the OD solenoid location? Newc

[Mac VP]

49-50 Ford OD transmissions in the convertible carried a modified mount for the overdrive solenoid. When Ford moved the rear support forward for 1951 the overall modification allowed them to eliminate the special solenoid mounting bracket for the convertible.S