gdmn852 Posted February 17, 2020 Share Posted February 17, 2020 Hello,has anyone fitted a Mitchell overdrive to a Closed drive shaft Buick, they seem to be used in Model A s and early V8 Fords?Thank you . Link to comment Share on other sites More sharing options...
Bloo Posted February 17, 2020 Share Posted February 17, 2020 (edited) I have not seen it in a Buick yet. I made inquiries when I was wanting overdrive in my torque tube Pontiac. MItchell (at that time anyway, about 3 years ago) do not support torque tube installations in anything other than the 2 types of car they make kits for. Those 2 are the Model A, and the early flathead v8 Ford. IIRC they would have sold me one in a white box, unsupported, with flanges, out the door for about the same cost as a Ford kit (within a buck or two). I would have been responsible to do all the engineering, machine work, welding, etc. to get it in there. I was fine with that, but I went a different direction. In retrospect I probably would have been better off going with the Mitchell. They do make a universal kit for open driveline cars. Edited February 17, 2020 by Bloo (see edit history) Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 Hello thanks for the reply, I had emailed them but got no reply so far . I know they can be fitted with a rebuilt overdrive by a place in Ohio,it might make it more enjoyable to drive, It has the 4.454 rear and with Dynaflow it needs it.Gary Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted February 17, 2020 Share Posted February 17, 2020 A 4.454 with Dynaflow! What Buick do you have? Ben Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 1949 Super Convertible with Dynaflow,I had to replace the rear end and that was what was in it and it needs that low end for acceleration, but engine turning lots of rpm at 60 mph . The 4.54 was also available in pre war Buick s ,many of the post war Super with Dynaflow were equipped this way. Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 The only other ratio available on 49 Supers was a 4.11 according to shop manual. 1 Link to comment Share on other sites More sharing options...
1939_Buick Posted February 17, 2020 Share Posted February 17, 2020 19 minutes ago, gdmn852 said: The only other ratio available on 49 Supers was a 4.11 according to shop manual. 2 hours ago, gdmn852 said: Hello,has anyone fitted a Mitchell overdrive to a Closed drive shaft Buick, they seem to be used in Model A s and early V8 Fords?Thank you . From 1940 to 1955 the diff centers will swap. So a bigger range of ratio. Look for 1950's dynaflow diff. You need to use your original torque as the length seems to vary year to year. Someone may know which are a 100% swap with the torque tube Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted February 17, 2020 Share Posted February 17, 2020 I am surprised as well as I thought the 4.454 was only used in the post war standard transmissions on the Super and Specials. Joe Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 Hello again ,I have a master part list that goes up to 1954 and it shows low gears available for prewar cars ,also the carriers change around 1948 to allow double row larger bearings on later rear carriers.want to keep the 4.54 but augment with OD .With a 4.54 rear on a standard shift car it would probably be almost stall free ,speed limits in that area were usually 50 mph except Pennsylvania Turnpike at 70 mph in late 1940,s so high rpm at higher speeds apparently weren’t a concern along with higher fuel consumption. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted February 17, 2020 Share Posted February 17, 2020 3 hours ago, gdmn852 said: 1949 Super Convertible with Dynaflow,I had to replace the rear end and that was what was in it and it needs that low end for acceleration, but engine turning lots of rpm at 60 mph . The 4.54 was also available in pre war Buick s ,many of the post war Super with Dynaflow were equipped this way. Well dang! According to the Shop Manual, nothing lower than 3.9 to 1 in a Dynaflow car in 1950. And I thought that was low. My Special with manual was 4.11 to 1. I changed to a 3.36 from a '55. Dropped RPM by 650 in third. 60_--70 in the mid 2000. Ben Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 I have a 1948 49 Manual,Buick may have changed to the slightly higher ratio with the 263 Eights,I know the rpms are high at upper speeds it’s too bad Buick never offered overdrive when new,Hudson,Studebaker and even 49 Ford had it as a option. Link to comment Share on other sites More sharing options...
Matt Harwood Posted February 17, 2020 Share Posted February 17, 2020 Gear Vendors. Expensive but worth every penny. A heavy car like that will tear up a Mitchell and the Borg-Warner, in my experience, is borderline unreliable simply because it wasn't designed to live there and the modifications make them finicky. And free-wheeling is downright terrifying with the B-W unit in a big car. A more wallet-friendly solution might be to find a later pumpkin with taller gears in it, as was mentioned above. Even a 3.90 gearset would make a significant difference if you're running 4.40s now. We had a 3-speed manual 1948 Super convertible and at about 50 MPH it sounded like it was going to fly apart. It probably wasn't in distress, but I understand why people with the small series cars are always looking to change gear ratios or add an overdrive. Much too much gear for today's world. Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted February 17, 2020 Share Posted February 17, 2020 I had a 3.36 put in a 1948 Special sedanet. I had thought I was buying a 3.60 from a now defunct Buick outfit in California but they shipped a 3.36. Worked OK but second gear was weak on hills but I could do 60-65 MPH with ease in 3rd but I never went above 60 because I knew stopping from 65 on bias ply 6.50/16 tires was too risky for me at my age. My 53 Special with a 3.6 with Dynaflow is very responsive and I can run at 55-60 MPH with no worries. Joe Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 Hello again, I did contact gear vendors with email and waiting a reply,would have to send them the torque tube and drive shaft, from experience in this town, no one would be capable of modifying the drive line.Not sure what would be best way to ship. Link to comment Share on other sites More sharing options...
Guest Posted February 17, 2020 Share Posted February 17, 2020 I don't understand. In the 60's I had a 2 door standard and a 4 door dynaflow Buick Special. I have absolutely no idea what the C&P ratios were but they were original from the factory. I was the second owner of each. With either of these cars I traveled back and forth from Winnipeg to Moose Jaw a 400 mile trip each way. Generally between 5.5 and 6.5 hours almost every week of the year, driving always in the middle of the night. Much less traffic then, some nights I would not see neither head nor taillights for maybe 40 or 50 miles. The engines ran great at 60,70,80 and 90+ indicated mph. One stop on the way for gas as the 20 gallon tank was too small. I think today people are too desensitized by our almost silent engines. If I had one today and if I were looking for an overdrive I would only consider Gear Vendors. Link to comment Share on other sites More sharing options...
gdmn852 Posted February 17, 2020 Author Share Posted February 17, 2020 Hello ,you are right with the newer cars with overdrive in does 70 mph at about 2000 rpm ,gas mileage on the 49 is only about 10 mpg .When I go to shows in it I rarely take Interstates mostly state and US highways speed limit 55 mph will easily creep up to 60. I do have a tendency to pay more attention to the older cars as I drive them, also to other drivers.Still I don’t want to throw a rod 49 Buick is out of warranty 😁 Link to comment Share on other sites More sharing options...
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