I THINK the overdrive transmission for a 1951 Mercury (straight shift) is a one year only transmission. Is this correct? How can I identify a 1951 Mercury Overdrive transmission? Thanks!
Also, join the International Mercury Owners Association (IMOA). They will know for sure. Also, get a copy of the manual shown below. It has a break down with pictorial dwgs of the 49-51 Merc overdrive units with part numbers.Very helpful as there appears to be lots of interchangeable parts from 1949-51.
Late 1951 has a one year only bell housing but the transmission itself is basically the same unit used in Fords and Mercurys with overdrive from 51 up into the mid 50s somewhere. The early 1951 Mercury had the same transmission as the 49 & 50 models and it has a little bell cast into the front of it requiring the partial bell housing used in many pick ups & trucks. The 49/E51 trans case is very similar in appearance to the 40 through 48 side shift trans case. The only thing that really changed it from the earlier Ford units was the lock out mechanism and the overdrive housing attachment on the back side.
I have a trans from a 50 Merc and it has the small bell housing like you are talking about, but the one out of my car (1951 Merc) does not. A buddy has one out of a 1953. Will that fit the 51 without modification?
The '51 eliminated the "Rail Switch" that the earlier models had, otherwise I believe the '51 is the same transmission, the R10 Borg Warner unit.
Late 1951 Merc bell housings are the ones you are talking about. I found a few back in the day and were most common with the O/D transmission cars. Scarce then and almost impossible to find in this day and age. '49 and '50 Merc transmissions were 8 bolt units, as were the early '51's but the late '51 Merc bell housing used the 4 bolt trans(way more common) WITH your stock Merc clutch linkage. All Merc bell housings after late '51 were stamped steel and not cast. Clutch linkage was way different....remember Ford and Merc went to swing pedals in 1952. Don't get stoked if you find a '51 "Baby Lincoln" with a like bell housing. That big 336.7 flatty had a huge bolt pattern on the block and will never even come close to fitting the 255.4 or the 239.4 block
The '53 should fit the engine bellhousing. Fords from '49 thru '64 and Mercs from late '51 thru '64 use the same bolt pattern. It is possible the rear mount pad may not be in exactly the same spot fore/aft and require modification of the crossmember.
Below is a '49-'50 (and early '51) Mercury OD transmission. Below is a '51 Ford OD transmission, and is exactly the same as regular production '51 Mercurys, except for the shift arms. The overall length is +/- 24", and the trans mounting pad is +/- 12" from the front face. The '52-'53 F/M transmissions are a little longer, and the mount may be located different.
The '49-'50 Mercury 1/2 bells are stamped steel, while '52-'53 Ford and Mercury used the same cast iron full size bell housing.
What? Not trying to confuse the issue but the hard to find late '51 Merc bell housing was cast iron and used the Ford and Merc 4 bolt transmission. The '52-'53 bell housing, cast or stamped would do us '49-'51 Merc guys no good at all, simply because of the change in 1952 to swing pedals. One picture you submitted shows the late '51 Merc bell housing in all of it's glory. Looks similar to a truck T-5 bell housing. I would like to meet the guy that can adapt a '52 or '53 bell housing to be used with the stock '49-'51 Merc clutch cross shaft linkage. Starter plates will not interchange either from early 8 bolt bell housings to the 4 bolt bell housing. VanPelt has good diagrams. It might call me a FNG but I have been playing with these cars for 45 years. Am I really that old??
The '49-'50 Mercs used a stamped steel 3" 1/2 bell (similar to the cast iron truck) for the round pattern trans. The '51s, as you stated, used a one-year-only cast iron full size bell with the '40-'48 clutch style release and new-for-Mercury 4 bolt trans pattern. The '49-'51 Fords used a stamped steel full bell with the new 4 bolt pattern and a unique angled starter plate (that many use with the wrong bell!). The '52-'53 Fords and Mercs used the same full cast iron bell housing with the modern clutch release lever. If you are referring to the second picture I posted, that housing sitting near the '51 Transmission is a H.D. truck 4-speed adapter, or more commonly known as a "hogshead", and not a '51 Merc. Vanpelts does have a couple of mistakes with pictures on his F/M bell housing page. The starter plate labeled Mercury is actually the angled '49-'51 Ford plate, and the stamped Mercury 1/2 bell on the right should have the starter plate with the angle bracket (that bolts to the '49-'50 Merc oil pan), and is shown correctly in a drawing farther down. If you open the link below, you will find pictures (and text) of all the various bell housings, starter plates and more from '49-'53 F/M. bellhousing.pdf
not wanting to hijack the thread but I have a ?. I have a 51 merc bell and non od trans. I have a 54 Studebaker t86 with a r10 od. Have not pulled the merc parts out yet. My question is do the merc and stude trans have similar bolt patterns and/or will the od from the stude fit the merc trans?
Never spent a lot of time under the pick-up trucks, they had the wrong engine. Stroke was too short in those flattys or I was busy grabbing the available parts off the top. Never could get enough generators, carbs, thermostat housings, distributors or fuel pump housings. That T-5 hogshead looks a lot like the '51 Merc bell housing though but I know it had 6 threaded holes on the transmission side to be able to use a 3 or 4 speed transmission.
I think I will have V8 Bob answer this one. If my memory serves me at all Studebaker was a lot like American Motors. Used parts from where ever they could get the best deal.
anthony myrick Re: 1951 Mercury Overdrive <hr style="color:#e5e5e5; background-color:#e5e5e5" size="1"> not wanting to hijack the thread but I have a ?. I have a 51 merc bell and non od trans. I have a 54 Studebaker t86 with a r10 od. Have not pulled the merc parts out yet. My question is do the merc and stude trans have similar bolt patterns and/or will the od from the stude fit the merc trans I am not sure if Studebaker used the same bolt pattern as a '49-'64 Fords/'51 '64 Mercs. I know the B/W transmissions were basically the same throughout the industry, and many parts are common, or can be interchanged, but input shafts, bolt patterns, trans mounts etc. may vary brand to brand. You'll know better when you pull the Merc trans and compare to the Stude. I am pretty sure some parts were common, like Bendix brakes, and possibly rear axle assemblies, but engines, bodies and frames were pure Studebaker. I should know more about the brand, having been in the South Bend area forever, (and worked at their old proving grounds). There are some members here, along with guys on the Ford Barn and Studebaker forums that are very knowledgeable with these B/W gear boxes and should be able to answer specific questions about them.
thanks, we are putting a stude flat 6 with a r10 od together at school. The plans are to install in a track style roadster. I have an extra r10 od and trans from the stude and was wondering if it would fit the ford for a future ford flathead project. I have already found tons of info here on these od units......Thanks
You are going to LOVE that transmission. Work out your rear end and tire size carefully to optimize your rpms. I've had my Borg Warner od for a dozen years in a daily driver only vehicle for a dozen years. Come back here for any set-up questions, a lot of knowledge here. Good luck, Cosmo in the '49
MarknCarole, I also have a 51 merc and if its okay would like to ask Cosmo49 set up for rear end and tire size? I have a late 51 manual 3speed and would like to know what are some good options? Thank you
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