Advice Needed About This Axle, Transmission & Tire Size Combination

Discussion in 'General IH Tech' started by TorqueMonster1, Aug 12, 2019.


  1. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    scoutboy74, How can someone tell whether they are looking at a trac-loc or a powr-loc?? Are these front, rear Or both? All Dana axles or just certain ones? All ratios??

    So powr-loc was on OR before 1970? And trac-loc was on OR after 1970?

    Sorry for asking for so much detail but I figure I might as well learn as much as possible when a new topic comes up. Thanks!! Mark
     
    Last edited: Aug 13, 2019
  2. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Google images or pictures in the FSM will aid in visual ID. Generally, these are in the rear, but can also be found in the front. Dana 27, 30, 44, and 60, but won't interchange between those sizes. The D27 was all but phased out by 1965. I can't give you a specific cut off date or chassis model number listing for the switch. It just happened sometime in 1970. Most new offerings for the upcoming model year tend to roll out in the fall, so I would hazard to guess that a winter/spring 1970 build date LSD would likely be a PL, while a summer/fall 1970 build could be a TL, but the only real way to know for sure is to pop the cover and look. You can't go by the warning sticker inside the cabin either. The IH supply of stickers claiming the vehicle had a Powr-Lok were apparently not exhausted until about three years after the switch. It's false advertising, albeit unintentional. They had to let people know that a traction device was installed and those were the stickers they had left over. Once that supply was gone, the new stickers didn't call out the brand of device. Just that a device was installed.
     
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  3. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    SO, In making sure I’ve got this and for other reads in the future, trac-loc AND powr-loc were the same thing (Both were limited slip differentials, meaning if you jack up the Scout so that the tires are off the ground and spin one tire the tire on the other side spins in the opposite direction). This limited slip differential (LSD) was an option that could be ordered on a Scout. And IH had two names for the LSD, powr-loc first then later called trac-loc.

    And, if this option wasn’t ordered then the Scout came with an open differential meaning that the tires spin independently of each other. Mark
     
  4. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    IH didn't make them. They sourced them from the manufacturer in each case. They're not the same by any means, but they're designed to perform the same function...that being to aid traction by directing power to the opposite wheel in the event that one side loses traction by way of clutches and springs. They're not a true locker, even though they're often referred to as such. Limited slip is the more accurate description. They were optional equipment on Light Line vehicles. Open diffs were standard.
     
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  5. Ron A

    Ron A High Wheeler

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    Picture is off the internet. If you have one it might ok, but I would be inspect one before installing one, and keep an eye on it at oil changes. The clutch pack keepers tend to fail and the clutches will spin. They can be replaced and new clutches will help restore function, but the cases themselves were prone to cracks. My first drive-train failure was when I sheared one in half. No big tires, just 31s, chains and deep snow. As to the economy of 3.07s vs 3.31 . It really depends on how and where you drive. I prefer them lower, but I can go from 2,000 feet to over 10,000 feet in about an hour. I also haul a trailer around.
     

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  6. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    Assuming the covers are off and you're you're actually looking at them, it'll be quite obvious. Probably best if you just google them to see pics rather than read written descriptions, etc.

    Nope. Not two names for the same thing. Two entirely different types of LSD, made by Dana, not IH.
     
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  7. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    The cut an turn makes good sense. The RS doesn't really make much sense if you aren't going to four-wheel it. If you just want a good ride, invest in good shocks. This is assuming you have a set of good springs all around. But if you don't, the RS would be an even bigger waste of time.
     
  8. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    I’m under the impression that the reverse shackle will be a much better ride and control when a Scouts Tires hot a hole. Could be a hole in the woods or on a trail OR a pothole in the city streets. I could be wrong or just not understanding it all.

    Let me ask this, Is there a down side to doing a reverse shackle? Other than the time, effort and money it takes is there a reason it shouldn’t be done? Mark
     
  9. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    You'll have that control if your have good shocks, properly valved, and springs. There might be a slight benefit to RS in certain situations, like in a high speed swerve perhaps., but that might be canceled out since it's not easy to run a front end sway bar with RS like you can with the standard suspension. And with RS there will be an inherent tendency for the nose to dive and weight to shift way forward under hard braking, which is the opposite of the tendency with a standard front suspension---stomping on the brake will cause the front end to lift up, or 'want' to lift anyway.

    I will admit, i've never ridden in a Scout with front RS. But I have ridden in a Scout with rear "RS", mine. It's what they all have. And I would never say that the rear rides inherently better than the front. Hitting a bump or pothole is always a double-harsh experience. That is except for the few months I had my rear 7100s valved kinda too soft in compression. The tail end of the truck rode like it was on air springs or something. Great around town but it turned out to be too soft for fourwheeling when the truck was loaded up with gear. But my front end? With the shocks the way they're valved now I can drive stright into a 6-8" curb and it feels like something half that high, or maybe feels just a steep ramp. It's hard to explain.

    But it's your money. Try it if you feel like experimenting. It's not a bad thing to do. But I'll be you won't get as much improvement as by adding a set of Fox 2.0 Emulsion shocks all around, tuned for soft compression and firm rebound, say their 30/70 valving or thereabouts. I HAVE been in a Scout with that setup, and it's phenomenal. But again, also decent springs. Not Rough Countrys or some other cheap set.

    FWIW Mark, I think the main reason for going RS on a Scout is that it's a strong setup for offroading. Way less worry of breaking a spring when you hit something abrupt at high speed. The springs are 'pulling' the front axle rather than trying to push it around (unless you're in 4WD, which reverses the situation). And leaf springs aren't really the ideal "swing arm" material.
     
    Last edited: Aug 13, 2019
  10. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    Thanks for the quick feedback Patrick. I'll continue to really think it through before I do anything. As of now, I'm planning on going to the Nats this coming weekend in Ohio so I may be able to talk to a few Scout II guys that have done the reverse shackle to their ride. As far as springs go, mine are the originals (as far as I know and can tell, pretty sure) With an add-a-leaf for just a hair of lift. What are your thoughts about that? Mark
     
  11. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    Well, the factory springs are probably fine and a good base for ride tuning. Add-a-leafs will make them stiffer of course. I only mentioned the Rough Countrys because most of the people who install them complain about the stiffness, and I don't know if that's too much stiffness to be 'fixed' just with softer compression damping. I guess RC spring 'technology' is to use fewer, thicker leaves in their packs. Makes for springs that don't like to flex. People buy them because they're the cheapest option these days. But people who go that way to lift their Scouts aren't spending $700-800 on good shocks, so it's really hard to make a comparison.

    If you're going to be doing all that other major work on it, new springs with a mild lift doesn't seem like a crazy idea. Like SkyJacker 2" springs. It's what I have and I've been satisfied with them for almost 20 years now. I am using their "helper leafs" in the rear pack for a little extra spring rate though. And I'm using longer shackles just in front, to balance out the height increase caused by the rear helper leafs.

    Going with an RS setup in the front will raise the front end slightly, so I was told by Jeff at IHPA. By exactly how much will depend on how you do the rear shackles. He said figure 1", give or take, and if my memory is any good. Just something for you to factor in if you go that route.
     
  12. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    Tell me this guys. What axle ratio would y’all want in a ‘73 Scout II, stock 345, T-18 Trans with 265 75 16 tires?? 3.07, 3.31, 3.54, other?? AND why did you choose that ratio?? I’ll be doing No off roading, no towing, just pleasure driving, shows etc... thanks again! Mark
     
  13. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    I don't know the diameter of that tire. Did someone say 31.5" earlier? If so, and if it were my choice I'd go with 3.54. It's what I have now. Works great with 31s and 32s. It's a good all-around gearing. Decent on the highway. I think at 65mph my engine's turning around 2500 or a hair under. And I can cruise at 75mph and it's not too bad on the ears.
     
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  14. mongocanfly

    mongocanfly Binder Driver

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    3.07 gears..1795rpm at 55
    3.31 gears..1936rpm at 55
    3.54 gears..2070rpm at 55
    3.73 gears..2181rpm at 55
    .....personally I'd want 3.54 or a little lower...maybe 3.73..just depends on what rpm your comfortable with..
    The trucks I've built I try to shoot for around 2000 at 65...
     
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