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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    Thanks for looking at my post. Got a question. I have a ‘73 Scout II, 345 V8, with a T-18 4 speed Transmission AND I currently have 265 75 R16 tires. If my axle ratio is 3.07 will I be ok? What I’m asking is will my Scout drive, accelerate, etc in an acceptable manor?? I will be doing NO off roading (hopeful not even a dirt road in this Scout). I won’t be going larger in tires. I won’t be raising cain in it. I won’t be towing anything with it. Just normal driving around town or on the highway for pleasure and to cruise-ins etc. So what can I expect? MPG? Performance? Etc?? It does have an add-a-leaf so everything clears. I’m thinking some of you know how to mathematically figure this out OR you just know from past experience. Thanks guys!! Mark
     
  2. 1975IH200

    1975IH200 High Wheeler

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    You'll be just fine.
     
  3. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    Please read again to be sure. My fat finger hit a 9 instead of a 8 on the transmission. I have a T-18 transmission. (I have since edited it to read correctly). Thanks, Mark
     
  4. mallen

    mallen High Wheeler

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    I think the T18 is close enough to a T19 that it should not make a difference. The highest gear is still 1:1. There are wide ratio and close ration variants of both transmission I beleive, so your low gear will depend on that, not t19 vs t18.
     
  5. 1975IH200

    1975IH200 High Wheeler

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    You'll be fine.
     
  6. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    Here is a copy of my LST if that helps confirm anything about the transmission. Thanks Again! Mark

    1E2AF52F-A13F-4B27-851A-0095B0DC9830.png
     
  7. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    LST says your axle gearing is 3.31. Did you swap axles?
     
  8. Scoutnap

    Scoutnap Farmall Cub

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    You will be fine. My 75 has a 304 , t18 and it had 3.07 gears with 31's until I broke them and it did fine. right now I am running 32's with 3.54 gears and it does fine for most things. Depending on your carb set up you can probably expect 11-15 mile a gallon.
     
  9. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    Yes scoutboy74, it currently has 3.31. I am wanting a Dana 44 front axle with disc brake. I have found one but it’s a 3.07. If it worked out I’d swap out both to the 3.07 IF there aren’t a bunch of reasons why I really shouldn’t.

    Thanks for the feedback guys. Mark
     
  10. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Given your stated usage plans, a D44 FA is overkill. Your present D30 FA will hold up just fine to daily driving on surface streets. There are disc brake kits available for the D30. That way you could retain both your present axles while still upgrade the braking capability. Just another option to look into, in case you weren't aware of another way to skin this cat that wouldn't involve axle swaps at both ends.
     
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  11. mongocanfly

    mongocanfly Binder Driver

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    Heres a rpm calculator thatll tell you what you need to know..
    http://www.csgnetwork.com/multirpmcalc.html
    With a tire dia of 31.6..trans gear of 1.1,,,3.07 gears and running 65mph you'll be turning 2122rpm
    Same setup but with the 3.31 gears itll be turning 2288rpm..
     
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  12. kdsmit

    kdsmit Farmall Cub

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    That is a VERY handy tool!!!! Thanks for sharing!!!
     
  13. Patrick Morris

    Patrick Morris Lives in an IH Dealership

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    If you just want front disks, then as Scoutboy said, just add them to your D30 FA. I don't see a reason to go through all the work of swapping both axles for just better brakes, and getting maybe unwanted taller gearing in the process. (Your 3.31 gear will be a little more responsive, accelerate slightly better, etc.)

    I was going to suggest that since you don't plan ever to take it on dirt you could just swap in the front D44 and never engage 4WD, don't even install the front driveshaft. But that would come back to bite you hard when you eventually try to sell the Scout. Much better to "do it right". So maybe start reading up on disk brake conversions?
     
  14. Ron A

    Ron A High Wheeler

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    If you want the Dana 44 swap, I would just change gears, replace the seals and check the bearings. Ring and pinion sets don't seem to be that expensive. Less hassle than swapping out both ends, especially if the donor rear needs work. Setting up gears isn't that difficult, but I would think a decent shop could do the work at a reasonable price, especially with it out of the truck. Considering the age of these things I would probably not install a donor rear end with out going through it. You really need to watch out for the ones that have trac-loks. Which brings you to what Scoutboy74 suggested , just installing disks on what you already have. Good time to replace the ball joints and check the tie rod and drag link ends, no matter which choice you make. Then you are good to go for another 40 years.
     
  15. mallen

    mallen High Wheeler

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  16. AdamT

    AdamT Farmall Cub

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    A question as I am currently pricing out a D44 front axle swap with cut & turn to gain disc brakes on the front and resolve a poor SOA install by a previous owner on my '72

    I keep reading that the disc brake conversion kits for Scout II will not work with stock rims. Anyone installed one of these kits and care to comment?


    Thanks


    Adam

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  17. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    No disc brake setup will work with your 1972 stock drum series rims due to caliper clearance issues. Stock disc series rims from a later year Scout that came standard with front disc brakes will clear. This would be model year 1975 and later as well as some, perhaps even most, but not necessarily all 1974 models. Wheels from mid 70's and up Ford 1/2 ton pickups and Broncos having front disc brakes and the 5 on 5.5 inch wheel lug pattern will also clear Scout II disc brake setups.
     
  18. AdamT

    AdamT Farmall Cub

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    Many thanks for pointing this out Scoutboy74.

    Would have been an unpleasant phone call to receive when the shop tried to put the tires back on

    Keeping the D30 is still on the table now as most my 4x4 use is steep driveways, logging roads and new roads being created. No rock-crawling planned.

    I know the local Scout parts guy has a number of sets of rims as we went through them in an attempt to find a matching rim for a spare tire. Will look into trading my rims in on a newer set + spare and doing the disc conversion.

    Any comments on power brakes with the thought of also adding power steering? Either at the same time as the disc brakes or a few months later for budget purposes.

    Engine is AMC 258 so I have yet to find definitive answers on power steering mounts and shaft lengths (replacement water pump did not match original so I foresee some fit challenges)

    Thanks


    Adam

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    Last edited: Aug 13, 2019
  19. TorqueMonster1

    TorqueMonster1 Farmall Cub

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    Thanks for the feedback guys. That’s a lot of good information. The main question I was wanting answered was about the motor, trans & 3.07 ratio axle. There’s more to my asking but I wanted to keep it simple.

    One thing- I’m considered taking the body off of a 1976 2wd Scout II and sitting it on a 1975 4wd frame that’s complete minus the body. Second thing- I do want disc brakes up front (on a different 4wd Scout II, a ‘73- the one described in the LST) and I could just do the conversion (anyone have a ballpark idea of the total cost for that??) but I’m also 99% sure I’m also going to do a cut and turn AND a reverse shackle so swapping the Dana 30 for a Dana 44 won’t bother me. If I went with the 3,07 axle then I’d need to also swap the rear SO that’s when I started wondering if there were any reasons not to as far as mpg, performance or drivability.

    Also, someone please explain what exactly is “trac-loc” and why I’d need to watch out for those. Thanks Again! Mark
     
  20. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Trac-Lok is a limited-slip differential that could be optioned On IH vehicles produced after a certain date in 1970. It is a notoriously weak design that has earned the nicknames Krac-Lok and Trash-Lok. The Powr-Lok limited slip that it replaced in 1970 is far more robust and superior in every possible way. Why IH decided to go that route is irksome to say the least, but was most likely an effort to cut production costs. All that said, My '74 Scout has a factory Trashy in the rear that I've wheeled fairly hard with larger tires for eons and it hasn't gone "boom" yet. Probably just a matter of time, though.
     

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