Announcement

Collapse

Get more Tips, Specs and Technical Data!

Did you know... this Forum is a service of the Studebaker Drivers Club? For more technical tips, specifications, history and tech data, visit the Tech Tips page at the SDC Homepage: www.studebakerdriversclub.com/tips.asp
See more
See less

2 speed rear end questions

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Rear Axle: 2 speed rear end questions

    Several...

    What units were on Studebaker trucks and how common was that option?

    Are they something that can be just swapped, rear end for rear end?

    Were they usually installed on particular trucks, other than the diesels?

    Just wondering...thank you for the lesson.

  • #2
    Two-speed rear axles on big trucks have been around since at least the early 1930s, and they have been a common option on all makes of truck with >1.5-ton capacity for that whole time. Studebaker did not build its own axles, but bought them from outside suppliers like Timken or Rockwell. These companies also provided axles to most of the other heavy truck builders. I think GM may have been the only heavy truck builder that had the capability to provide its own axles (but GMC trucks could still be ordered with other axles). As a result, the internal guts of the same model axle can be swapped, no matter what make truck it's under. But some attributes (spring perches, overall length, brake hardware, wheel bolt pattern) might/might not be different and unique to Studebaker. So one needs to be careful that any complete replacement axle unit will fit without modifications.

    Axle technology has advanced through the years, so the same model axle typically was only used for 6 or 8 years before being replaced by a newer model or one from a completely different supplier. As shown by the parts books, Stude bought its truck axles from just about everybody -- sometimes using one supplier for the 1.5-ton E28 and another for the 2-ton E38. That said, Stude's big truck engineering was moribund throughout the 1950s, so a complete 1964 8E40 two-speed axle unit will probably bolt right up under the frame of a 1949 2R17A. However, the internal guts will be different -- for one thing, the older units used vacuum to shift, while the later ones (post 2E?) used electric shift.

    A lot of us wish we could get more top speed out of our big trucks, but it's tough with axle ratios around 6:1 (high) and 9:1 (low). The advent of the V8 in the 3R models helped a bit, but 50 mph seems like the practical limit for Stude's big trucks. Better, higher (lower numerical) ratios were simply not available for these trucks (or anyone else's trucks either) in those days. Obviously, if one is willing to spend some serious bucks for fabrication, a modern higher speed axle and/or a Brownie auxiliary transmission can be installed on an old truck. There are several very nice such modified Stude trucks in SDC. For today's hobby truck, the two-speed rear axle is a useless anachronism -- no one ever uses anything but high ratio. And going to a single speed usually means replacing the whole unit -- and the ratio will not be any better than the high ratio of the two-speed unit.

    An old (Hollander's?) Truck Interchange Manual would provide info on what other model axles might interchange, but I am not aware of anyone reprinting them.
    Last edited by Skip Lackie; 09-23-2014, 12:28 PM. Reason: Added sentence
    Skip Lackie

    Comment


    • #3
      Skip covered these axles very well here for you. As far as usage, yes they were optional but all the ratios I see in the Parts Catalog were usually Lower or the same in Low or High than a single speed. You have to remember that all Trucks of the era had closer to 100 than 200 H.P. so to haul a load the axle ratios HAD to be in the 6's thru the 9's to 1, to get the job done.

      And when you saw a Truck on a single lane road you knew you were going to have to slow down and wait, if a hill was involved you would be crawling.

      A very large amount of 2 Ton, Big Six Four Speed, 2 Speed axle Trucks were sold to Farmers that did much of their driving off-road and that Commander Six would pull with the best of them and better than most.
      StudeRich
      Second Generation Stude Driver,
      Proud '54 Starliner Owner

      Comment


      • #4
        Thank you both. I have read threads about them in the past here and there, but I was left with the impression that a 2 speed rear end allowed the big trucks to get to 55-60 on the freeway. I wanted to get that clarified as I was aware they weren't a common option and IF that were the case there had to be some reason they weren't used or sought after more.

        Another simple wheel question about the big trucks, can you remove the inner set of wheels on a dually and just bolt up the outer wheel and drive the truck with a single set of rear wheels, or is there more involved in doing that?

        Comment


        • #5
          Originally posted by LeoH View Post
          /Cut/Another simple wheel question about the big trucks, can you remove the inner set of wheels on a dually and just bolt up the outer wheel and drive the truck with a single set of rear wheels, or is there more involved in doing that?
          Sure you can, in fact the standard practice was to not carry a spare, and when a front Tire blows, to just take one from the rear.
          Of course if you had a full load you would probably exceed the Load Limit for that one tire, but Bias Ply, Tubed, Trucks tires were 8 or 10 Ply and pretty tough so you may or may not be Ok.
          StudeRich
          Second Generation Stude Driver,
          Proud '54 Starliner Owner

          Comment


          • #6
            On swapping the whole unit. First Budd or Dayton wheels? If Budd is it 5, 6 or 10 lug? Measure the center of the spring distance. Then jump in with a Ford, Dodge or International. No rocket science. I used a Ford in my 47 Stude.

            Comment


            • #7
              I had a Columbia 2 speed rear axle in my 48 Mercury.

              Comment


              • #8
                Originally posted by ST2DE5 View Post
                I had a Columbia 2 speed rear axle in my 48 Mercury.
                Ok. That sounds like an interesting story....

                Comment


                • #9
                  Originally posted by Flashback View Post
                  On swapping the whole unit. First Budd or Dayton wheels? If Budd is it 5, 6 or 10 lug? Measure the center of the spring distance. Then jump in with a Ford, Dodge or International. No rocket science. I used a Ford in my 47 Stude.
                  Well, that is something to be aware of. I expected that most trucks would have the same sets of wheels on the front and the back, but, you're right over time a used truck might end up with a different brand of wheels on the front and the back.

                  Comment


                  • #10
                    https://www.google.com/search?q=colu...g.mozilla:en-U

                    Comment


                    • #11
                      Originally posted by LeoH View Post
                      Thank you both. I have read threads about them in the past here and there, but I was left with the impression that a 2 speed rear end allowed the big trucks to get to 55-60 on the freeway. I wanted to get that clarified as I was aware they weren't a common option and IF that were the case there had to be some reason they weren't used or sought after more.
                      Unfortunately, the two-speed rear axles were there to provide a LOWER axle ratio, not a higher one. So you have a choice between slow and slower. As an example, the highest ratio available in an E40 with a single speed axle was 6.20:1, while the highest available in a two-speed axle was 6.16:1. Obviously not worth the trouble to make a swap unless one could replace the axle with a much more modern unit.

                      I am not aware of any data on what percentage of Stude's big trucks were equipped with the two speed rear axle, but I suspect it was more than half. Most of the larger old trucks (all makes) that are advertised for sale in the ATHS magazine are equipped with them. So I would claim that they were a very common option on trucks of 2 ton capacity or more.
                      Skip Lackie

                      Comment


                      • #12
                        Wow. I was mistaken. I was under the impression that the 6:1 and 9:1 ratios were for the Low gear and not the high gear! That explains a lot.

                        Comment


                        • #13
                          Interesting.

                          Comment

                          Working...
                          X