Transmission and Transfer Case suggestions please

Discussion in 'General IH Tech' started by Chad Bailey, Sep 9, 2020.


  1. Dreamingofbinding

    Dreamingofbinding Farmall Cub

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    I know I replied somewhere else, but I would NOT regear your transmission and transfer case. If you want taller gears, I'd either go taller tires as winchested suggested (though that can introduce handling concerns) or have the front and rear differentials regeared. If you have a tach today, you can see what RPM ranges you're using in your drives now, and you can then easily calculate what change from current gearing would benefit you.

    You might have 3.73 gears now. If you do (you'd want to confirm this), you could go to 3.08 or even 3.43 and it would drop the RPMs for the same gear and speed proportionally. For example, if you're running at 2500rpm at a certain speed now, and go from 3.73 to 3.08, you'll drop about 400 RPM to go the same speed.
     
  2. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    Not even on the table since it's pretty much impossible to do. At least not in a way that the OP would want.

    I've never heard of any optional gears for a T19 type transmission. I think we're all 'stuck with' either the standard close set or the wide set. And even if the OP wants the wide set for some reason, where are you going to find all the gears etc etc to do the job that aren't already in an assembled T19 that's ready to go? Might as well swap out the whole transmission.

    The only gear options for the TC affect just the low-range gear. High is still 1:1 no matter what.
     
  3. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    To add, there are no flaws in the design. It's simply a medium-duty truck driveline you're dealing with. Maybe you should consider converting it to an Automatic trans? I hear they're nice. TF727 I think is a straightforward swap. And a lot of people here have done the swap in one direction or the other.
     
  4. Chad Bailey

    Chad Bailey Farmall Cub

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    The motor is a newly rebuilt 345 by Scout Connection, rear axle is Dana 44 w/3.54 ratio. Front axle is Dana 30. I believe both axles are original to the vehicle, judging by the line set ticket and what I see on the Scout.

    Thanks for your time and assistance. Very much appreciated.
     
  5. Chad Bailey

    Chad Bailey Farmall Cub

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    Thanks, this is what I need to hear. None of what I'm dealing with is a big nuisance. Rather, I'm trying to understand what options are reasonable to consider before diving into a rebulld.

    Not having driven any other Scouts besides this one and my prior 79 (345 w/3 speed manual trans) I don't have much else to compare to.

    I certainly appreciate all the input very much!
     
  6. Chad Bailey

    Chad Bailey Farmall Cub

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    Will keep this in mind, but I just love having an old manual. I think I'd sooner stick with what I have than go to an auto.
     
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  7. Chad Bailey

    Chad Bailey Farmall Cub

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    Yes, I do need a tach as I'm just feeling and listening to judge at this point. I just feel like I hit a weird ceiling at around 55-60mph that feels uncomfortable to push beyond.
     
  8. winchested

    winchested Y-Block King

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    What size tires are you running? 31s to 33s would be fine with that trans and gearing combo.
     
  9. WRENCH MAN

    WRENCH MAN Dreams of Cub Cadets

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    A '75 should have Dana 44's in both ends?
    as stated you're not going to get any higher gears for cruising, you can go two ways for more low gears, swap to the wide ratio T-19 or (it's getting harder to find the parts) since you have a manual transmission, you can gear the transfer case down to the Bronco 2:46 ratio, but you'll need to find ALL the donor gears.
     
  10. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    If they're the same tires seen in his avatar then they on the smallish side. Could be 31s. So as you say, it should be fine. The 3.54 gearing with 31s will allow 70 MPH cruising. At maybe 3000 RPM? Give or take a hundred. This is partly dependent on the speedometer being accurate. LOL

    Yep. Sounds like your next move is to install a tachometer. I suggest you put in a 4000 RPM tach, since that's all you will need and it gives you a better scale, easier to read.

    This VDO model below is probably fairly easy to find and is among the least expensive at ~$80-100. Not too big either. But there are other makes, like Datcon (what I have) if you want a larger dial.

    Click here to see the examples that Summit sells: https://www.summitracing.com/search/part-type/tachometer-gauges/gauge-range/0-4-000-rpm

    [​IMG]
     
    Last edited: Sep 16, 2020
  11. Chad Bailey

    Chad Bailey Farmall Cub

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    Currently have 28s and eventually will do a lift and run 33s.
     
  12. Chad Bailey

    Chad Bailey Farmall Cub

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    Yes, the tires are definitely on the small size... 28s. My plan is to do a lift and run 33s eventually.

    Thanks for the tach link. I'll dig into that.

    Appreciate all the input and suggestions!
     
  13. Chad Bailey

    Chad Bailey Farmall Cub

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    Actually have a Dana 30 up front and 44 rear.

    Based on what I'm hearing from others, my plan to run a larger wheel/tire combination in the near future may help resolve some or all of what I'm dealing with. Hoping that means my gearing can stay as is!
     
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  14. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    I almost hate to ask. Does your Dana 30 have disk brakes? If not, larger tires won't be much fun to stop. The "taller gearing" you get with taller tires has a similar effect when stopping. The brakes work harder.
     
  15. Ron A

    Ron A High Wheeler

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    The 28" H78-15 was a standard tire size back in the day but nobody was trying to cruise down the roads at the speeds they do now. Lower gears were the norm, but 3.54s are not all that low. The trouble with changing gears and overall effective gearing is the expense. What I would do is hunt down a tire shop that will work with you and tell them you are shopping for tires and have not picked a size yet. See if they can mount up a set of used take off tires to try. Go with 31s then 33s. 32s if they have them. A tachometer and a co driver with a gps can help you determine actual rpms and speed since the swap will require re-calibration of the speedometer. Been a while but my old 72 had an AMC V8 3.73s and 31s. I drove it everywhere, including a cross country trip and thought that gearing was pretty darn good. Running your ratios you are turning around 3050 rpms at 70 mph now. 31s with get you down to around 2750 and 33s to about 2600. Give or take depending on the actual rolling radius and how true the tires are to size.
     
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  16. Chad Bailey

    Chad Bailey Farmall Cub

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    Yes, my front Dana 30 does have disc brakes. Your point is a good one.
     
    Last edited: Sep 17, 2020
  17. Chad Bailey

    Chad Bailey Farmall Cub

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    Thanks, Ron. I like your idea of doing a test spin on some old tires first. Makes a lot of sense, starting with some 31s. Good call.
     

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