4:55 rear end

SuperDave
SuperDave Senior Contributor
edited November -1 in HUDSON
My 49 Super six has overdrive, so it has the standard ratio for that pkg. IE 4.55. Since I live and do most of my driving in Flat Florida AND I have some performance enhancing options, like Twin H (Hornet carbs) milled head, Pertronix ignition and 12 volt system, I really think i could do well with a 4:10. This is the early, Welded cover differential. I realize that the later differential is a better set up, but I would like to just swap out the center section and the speedo drive gear. Does anyone have a good one they would sell and/or swap? Mine is a 71,000 mile car, just replaced the pinion seal. It runs nice and quiet.:)

Tanks, Dave W. Fl

Comments

  • Jon B
    Jon B Administrator
    I don't have one for sale, but I think you're right to change over. I have a '37, which has much less HP than your car. I retrofitted an overdrive tranny into it and retained the 4.10 rearend ratio. Yes, the car is anemic on long, steep grades but for 95% of my driving the combination (OD + 4.10) has been just fine. And that's with 101 hp.; it should be even better with an engine like yours.
  • kamzack
    kamzack Senior Contributor
    SuperDave wrote:
    My 49 Super six has overdrive, so it has the standard ratio for that pkg. IE 4.55. Since I live and do most of my driving in Flat Florida AND I have some performance enhancing options, like Twin H (Hornet carbs) milled head, Pertronix ignition and 12 volt system, I really think i could do well with a 4:10. This is the early, Welded cover differential. I realize that the later differential is a better set up, but I would like to just swap out the center section and the speedo drive gear. Does anyone have a good one they would sell and/or swap? Mine is a 71,000 mile car, just replaced the pinion seal. It runs nice and quiet.:)

    Tanks, Dave W. Fl



    Hi Dave,



    I agree,with your ratio change. the reason I'm responding is; when I lived near Newberry,Fl,I used to spend alot of time at Don Whitaker's place, east and a little north of you. I can't think fo the name of the town he's near,but just south of Wildwood. His son is a wizard of an engine builder and a good group of people. He also has parts and can advise you on your swap. He has a lifetime of knowledge, I hope he's still with us. Let me how it all shakes out.

    Tanks,

    Kim
  • MikeWA
    MikeWA Senior Contributor
    Of a more general nature, what are the rear end ratio possibilities? I have a '48 w/ OD, so am assuming that I have 4.55 ratio (OD not working- or at least I don't know enough to make it work- and I can go 65 comfortably, 70 but am grating my teeth). So apparently 4.10 is standard for non-OD- what other ratios are available? Am assuming something in the low 3's for automatic- anything else? How about compatibility between years? Have thought about an automatic, for driveability reasons. Thanks for any replies.
  • J Spencer
    J Spencer Expert Adviser
    SuperDave wrote:
    My 49 Super six has overdrive, so it has the standard ratio for that pkg. IE 4.55. Since I live and do most of my driving in Flat Florida AND I have some performance enhancing options, like Twin H (Hornet carbs) milled head, Pertronix ignition and 12 volt system, I really think i could do well with a 4:10. This is the early, Welded cover differential. I realize that the later differential is a better set up, but I would like to just swap out the center section and the speedo drive gear. Does anyone have a good one they would sell and/or swap? Mine is a 71,000 mile car, just replaced the pinion seal. It runs nice and quiet.:)

    Tanks, Dave W. Fl





    My 51 Pacemaker coupe had 4:55's in it when I got it (overdrive) I ran it for many years like that. At 70 MPH it was turning around 2600 RPM. I got the car in 1988 and in 1999 I installed the 4;10's in it. Now it is about 2300 RPM's at 70.



    Yes it has lost abit of power on the hills, but it is worth the trade off. Might even realize a small mileage gain on expressways - long runs.



    A 3rd meber from a 48-51 with standard tranny bolts right in. A4.55 ratio in overdrive equats to a 3.20. A 4.10 equats to a 2.87 in overdrive.



    To determine engine RPM' at a given speed the formula is final gear ratio X MPH X 3.36 divided by outside tire diameter = RPM.



    Example 4.10 minus 30% O/D reduction = 2.87 X 60(mph) X 3.36 =578.592 divided by 29 (diam) = 1995 RPM. You don't have to put in the decimal points if you don't want to -- it's quicker that way.



    Hudson O/D's are a 30% reduction. I have had a tach on mine for test purposes and the meter verifies the formula.



    Hope this helps



    PS some with the larger engines have put in Automatic gears from 51 stepdown 3:59's. My friend has those with O/D in his 49 Commadore 262. Gotta tell you at 70 it's like being in a new long geared car



    Hudsonly



    JSpencer



    Don't forget to inspect all bearings in the differential. they are readily available at regular parts stores.
  • Unknown
    Unknown
    You'd do great with a 4.10. Not too low not too high. Because of driving habits back then it seems that all cars were geared like rock climbing Jeeps. The '29 came with two ratios, 4 1/13:1 and 4 5/12:1. How's that for fractions. The 4 5/12 = 4.42:1, and that's what I have, and up on highway speeds it really screams. The other is a 4.08 and I'd love to have that gearset. People in hell want ice water, too.



    By contrast my 65 Plymouth is a 2.71:1 rear end, and doesn't start running until it hits 70 mph.
  • Hudsy Wudsy
    Hudsy Wudsy Senior Contributor
    Guys I think that you are all wrong about these ratios. I don't have the time (story of my life) right now to research this, but I'm sure that the 4:55 (4:56, actually) is the Drivemaster rear end ratio. As I recall, the overdrive equipped cars had 4:10 rear ends and the standard non-overdrive cars had 3:70 rear ends. If I'm wrong I appologize. I hope someone with a better memory will weigh in.
  • nick s
    nick s Senior Contributor
    James P. wrote:
    Guys I think that you are all wrong about these ratios. I don't have the time (story of my life) right now to research this, but I'm sure that the 4:55 (4:56, actually) is the Drivemaster rear end ratio. As I recall, the overdrive equipped cars had 4:10 rear ends and the standard non-overdrive cars had 3:70 rear ends. If I'm wrong I appologize. I hope someone with a better memory will weigh in.



    james i have looked into this recently so it is fresh in my mind.



    the 3.70 was optional without overdrive with the 4.10 as the norm. the earlier posts are correct 4.56 was the norm with O.D.(the 4.10 was optional)



    drivemaster cars were the same as their standard counterparts. at least for the stepdown era. earlier may be different as i believe the transmission was geared differently w/ drivemaster while stepdown drivemasters use the same gearing as the standard transmission.



    James perhaps for the area you live due to road, terrain and traffic conditions, the cars tended to leave the factory with 3.70 w/o O.D. and 4.11 w/ O.D.
  • 464Saloon
    464Saloon Senior Contributor
    nick s wrote:
    james i have looked into this recently so it is fresh in my mind.

    the 3.70 was optional without overdrive with the 4.10 as the norm. the earlier posts are correct 4.56 was the norm with O.D.(the 4.10 was optional)

    drivemaster cars were the same as their standard counterparts. at least for the stepdown era. earlier may be different as i believe the transmission was geared differently w/ drivemaster while stepdown drivemasters use the same gearing as the standard transmission.

    James perhaps for the area you live due to road, terrain and traffic conditions, the cars tended to leave the factory with 3.70 w/o O.D. and 4.11 w/ O.D.

    According to my Hudson manuals, 4.56 is standard with O/D. My 54 special has the 4.56 and they in my opinion are ridiculous for a slow turning high torque engine like the Hudson 6. My O/D stuff was all bypassed and tied into a toggle switch so I just leave it on all the time, except you can't back up unless you switch it off. If you have a 308 with any modifications you could easily go with the 4.10 or even higher. I would have done it by now if I wasn't working on more pressing things on the car.
  • Geoff
    Geoff Senior Contributor
    464Saloon wrote:
    According to my Hudson manuals, 4.56 is standard with O/D. My 54 special has the 4.56 and they in my opinion are ridiculous for a slow turning high torque engine like the Hudson 6. My O/D stuff was all bypassed and tied into a toggle switch so I just leave it on all the time, except you can't back up unless you switch it off. If you have a 308 with any modifications you could easily go with the 4.10 or even higher. I would have done it by now if I wasn't working on more pressing things on the car.



    I agree, the standard package for all models with overdrive (Except Jet) was for a 4.55 rear end. The Jet standard o/d ratio was 4.27. The recommendation for city driving was to leave the car in 2nd gear, and overdrive enabled. This meant you could drive between traffic lights, and cruise wihtout changing gear - take off in 2nd, accelerate to 25 m.p.h., lift foot and you were in to 2nd o/d, which isn't far off top gear. Saved changing gears. However, any model can cope easily with the 4.1 back end, particularly the Hornet, and I intend changing my rear end over eventually. I did this with my previous '50 Pacemaker, and sure it was a bit gutless on the hills, but it sure was unburstable on the flat. One thing to be careful about with all models though, but particularly the 308, is to not use the kick-down unless in an emergency. This causes great torque stress on the clutch input shaft, and I have seen these with a corkscrew twist in them. Think about it, an instantaneous shift of 30% in speed between the input and output when kicking down from o/d to top gear, and it all has to be taken up in the clutch. If the twist gets too accentuated it gets to the point where the spline jams, and the clutch plate won't release easily.

    Geoff.
  • SuperDave
    SuperDave Senior Contributor
    Well I guess I am heading in the right direction. lots of encouragement from the board.. Now who has one they are ready to part with? Any 48-51 three speed with out overdrive will work.. Still looking.. Oh I do plan on being at the Pigeon Forge meet..Hint hint...:rolleyes:

    Dave W. Fl
  • Unknown
    Unknown
    Much of the information in these threads are incorrect or incomplete. Factory repair manual reprinted by Jack clifford in 1967 and 1972 covering model years 1948 - 1952, Rear Axle section 11, page one reads as follows:



    Models 4B-5B Ratios

    Standard Transmission (4-1/10 Std) (4-5/9 Opt)

    With Hydra-Matic (3-7/12 Std)



    Models 6B-8B

    Standard Transmission (4-1/10 Std) (4-5/9 Opt)

    With Overdrive (4-5/9 Std) (4-1/10 Opt)

    With Hydra-matic (3-7/12 Std)



    Model 7B

    Standard Transmission (4-1/10 Std) (3-7/12 Opt) (4-5/ Opt)

    With Overdrive (4-5/9 Std) (4-1/10 Opt)

    With Hydra-matic (3-7/12 Std)



    Hope this information has helped

    Fred
  • Uncle Josh
    Uncle Josh Senior Contributor
    Hey guys, I mount my kickdown switches near the clutch. I can kick it down any time with little or no torque from the motor. Very seldom do you need to kick it down under full power.



    As a bonus, you can split shift the tranny using all 6 gears if you want to, by hitting the KD switch with your heel as you push the clutch. 2nd OD to standard 3rd will raise your hood.
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