I want to lower my engine Rpm @ highway speed, I have a 1953 special

[Guest DaveLantz]

Where can I get a lower ratio center section for my rear end?

[Joseph P. Indusi]

I think the 1953 Special with Dynaflow came with a 3.6 to 1 ratio while the standard transmission came with a 3.9 to 1 differential gearset. I know the Dynaflow cars were geared about right giving good stop and go performance and comfortable cruising about 60 MPH. IF you have a standard shift, you could install a pumpkin from a Dynaflow car. IF you want to go still taller you will need to go to a 1954-55 V-8 car and these come in around 3.36 to 1 and 3.41 to 1. In my view, the 3.6 will be the best overall. You will need to find a car in a scrap yard or contact one of the Buick parts firms that may have cars they are parting out.

Joe, BCA 33493

[Guest kaycee]

I think the 1953 Special with Dynaflow came with a 3.6 to 1 ratio while the standard transmission came with a 3.9 to 1 differential gearset. I know the Dynaflow cars were geared about right giving good stop and go performance and comfortable cruising about 60 MPH. IF you have a standard shift, you could install a pumpkin from a Dynaflow car. IF you want to go still taller you will need to go to a 1954-55 V-8 car and these come in around 3.36 to 1 and 3.41 to 1. In my view, the 3.6 will be the best overall. You will need to find a car in a scrap yard or contact one of the Buick parts firms that may have cars they are parting out.

Joe, BCA 33493

Joe is right. If you own a car with a standard transmission you can benefit by installing the Dynaflow geared rear axle. I had a '50 Super with standard transmission that I switched rear end to a Dynaflow rear axle and it would run up to 85 mph in 2nd gear and hit over the 100mph mark with no problem.

kaycee

[Guest DaveLantz]

Thanks Joe and Kaycee,, any specific places you guy's would try first other than the links here on this site

[old-tank]

http://forums.aaca.org/f117/1954-buick-dynaflow-rear-end-347256.html

should be 3.6 gears...

[Leif Holmberg]

Here are some specifications on Buick ratios.1955 are the last year you can use parts from.1956 has a different splines.

Leif in Sweden.

[old-tank]

Here are some specifications on Buick ratios.1955 are the last year you can use parts from.1956 has a different splines.

Leif in Sweden.

Leif

The attached thumbnails are apparently the available replacement sets available in 1956. I know that 54 and 55 early used 3.41 gears in the 50-60-70 series dynaflow cars; late 55 used 3.36 gears in those cars...the ratio was so close that the same speedometer gear was used.

The 'for sure' verification is to divide pinion tooth count into the ring gear tooth count. Use the whole center section vs ring and pinion to avoid case incompatibilities and adjustments.

Willie

[Ben Bruce aka First Born]

David, do you know what ratio your car has? If it is a 3.9:1, A 3:6 would not be enough change for the effort, in my opinion. My '50 had a 4.1:1 and I changed to a 3.36:1. The 3rd gear rpm dropped by about 650 rpm .

This ie not an easy swap, but very doable. The entire rearend needs to be removed from beneath the car, remove axles, remove torque tube, remove drive line[pilott shaft, in Buick speak], remove the gears [pumpkin] as a unit, then reinstall all in reverse order. Not really compliocated, but a workout. I did mine with no help, other than advice. Alot of that from Willie and others.

Ben

[Guest DaveLantz]

Ben Where did you get the new gears you installed?

[Ben Bruce aka First Born]

David, mine came from another Buick member. They are from a '55. You want the whole "punkin". I would think if you advertise in the buy and sell forum , you should get some hits/

Another idea, although more pricey, is to add an overdrive. There are a couple places do this for our torque tube drives.

Ben

[Guest DaveLantz]

Can you tell me more about the overdrive add on's?

[Guest 54fins]

There are overdrives but you would need an open drive shaft. Older cars never seemed to care much about highway gears. If you want overdrive or higher ratios (I sure do) you have to use a more modern transmission and get rid of your torque tube. This is major surgery and there is no simple way to do it. First problem is the torque tube setup has you limited to just a few gear sets on the rear end. I do see a 3.08 and a 2.78 for a 59. Even if they would fit, finding them would be very difficult. The 2.78 would get you a good highway ratio for 65 plus all day cruising. Otherwise, it would hardly be worth the trouble. Then you would still have the dynaflow. This is where you cut over to the "modified" section and start building a new frame for your car. May as well improve handling while you are at it. It's an age old dilemma- do I enjoy the nostalgia of an original car or do I update it? There isn't a simple solution

[Ben Bruce aka First Born]

Not so, 54Fins. There are at least two sources for overdrives for torque tube cars. I just can't seem to recall the names at present, and don't have access to my records at the moment. AHA, one just came to mind. Gear Vendors. The other is an individual in Ohio. They are pricey, around $2500.00. Changing the gears in the rear end is way less.

Ben

[Guest DaveLantz]

Can Someone tell me how buick divided up the ratios,

10 teeth on the pinion and 34 teeth on the ring gear ?

3.36 to 1 and 3.41 to 1.

I'd like to look at a center section count the teeth on both and divide.

When I pull mine out will i see 10 on the pinion and 39 on the ring ,, I believe I have the 3.9 to 1 in it now .

[Ben Bruce aka First Born]

The ratio is stamped on the bottom of the housing. Ring and pinion are matched sets and should never be separated, per Buick. Do you have a shop manual?

Ben

[Guest DaveLantz]

Thanks first born for the info,,, so i have the 3.9

I'm not taking mine apart until i have another one

But What I wasn't clear on is :Are all the buick center sections the same pinion gear? Will they all fit with the torque tube driveshaft (1940 to 1955)

10 teeth on pinion

So an 3.2 would have 10 teeth on pinion and 32 on ring or something like 12 on pinion and 38 on ring

So an 3.4 would have 10 teeth on pinion and 34 on ring or 13 pinion 44 ring

I might have a contact that has one,,I was trying to tell them how to count teeth to figure it out

3.36 to 1 and 3.41 to 1. from old tanks info,,, has me trying to get more specifics.

What is throwing me off is the decimal .06 or .01

[Ben Bruce aka First Born]

NO , they are not the same pinion gear. As I said before, the pinion and ring are a matched set from the gear factory. The actual ratio, dividing the pinion teeth into the ring teeth, on mine any way, comes out to 3.36. I just round that off to 3.4. Somewhere, I can't remember just where, on one or the other, the number of teeth is inscribed. I will see if I have a picture of that.

Having said all that, you will gain about 12%, if my math is correct. At highway speed, that translates to about 350 rpm. Is this enough gain for all the work? I went from a 4.1 to 3.4[ all right, 4.11 to 3.36] This is about 19%. About 660 rpm. Almost twice as much.

Ben

[1939_Buick]

10 teeth on pinion

So an 3.2 would have 10 teeth on pinion and 32 on ring or something like 12 on pinion and 38 on ring

So an 3.4 would have 10 teeth on pinion and 34 on ring or 13 pinion 44 ring

While they both may have 10 teeth on the pinion, they will be machined to match the number of teeth on the ring. The teeth shape - spiral will be different.

There is a surprising number of Buick part numbers for the ring & pinions. I have done a (partial) study of these. Example: multiple part numbers with 10 teeth pinions even when matched to the same number of teeth on the ring.

There are different methods to change the ratio. A good thread here on H.A.M.B. Technical For you Buick Torque tube guys that’s want to change gear ratio - THE H.A.M.B.

....When I pull mine out will i see 10 on the pinion and 39 on the ring ,, I believe I have the 3.9 to 1 in it now .

There are people out in Buick world who would like your 3.9. A lot have 4.44 Edited April 14, 2013 by 1939_buick (see edit history)