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    1. #1
      Join Date
      Sep 2007
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      424

      T56 Magnum - am I the only one frustrated by the gearset choices?

      Speaking about the bottom 4 gears here.



      OEM manual trannys (on all cars in general) normally get a low 1st gear, a big gap between 1st/2nd, and the gap steadily closes from there on up. The wide-ratio TKO-500 (5spd) does this in a big way.

      There is no way to get this with a T56 Magnum. Not with any combination of rearend & gearset.

      The 2.66 gearset has a good pattern to the gaps, but it's still a close-ratio spread in the big picture. The 2.97 gearset has a fairly low 1st gear but the 2nd & 3rd are too close to it. It still doesn't really function like a wider ratio in practice. Not for the first 3 gears anyway.


      Why can't Tremec offer a T56 Magnum ratio like what is normal on most cars? Tremec builds many production-car TR6060s with spreads like this.

      (It's not possible to piece together a T56 magnum this way using existing pieces. I looked into it. The bottom 4 gears are basically all-one-piece and cannot be swapped around individually. Production TR6060 gearsets won't bolt into the Magnum case. Etc.)


    2. #2
      Join Date
      Jul 2019
      Posts
      2
      I am actually quite happy with their close ratio gears. They were really close to the factory 4sp gears that I was used to in my 68 Coronet

    3. #3
      Join Date
      Apr 2006
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      Huntington Beach, CA
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      What do you want?

      "normal on most cars" is the 2.66 gear set offered in the Magnum. I'd venture 99% of T-56 equipped OEM cars had that gear set. You can see a table of them from wikipedia here: https://en.wikipedia.org/wiki/Borg-W...6_transmission

      Only a few oddballs had the 2.97 or something different than the 2.66 gear set.
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    4. #4
      Join Date
      Oct 2018
      Location
      San Jose, CA
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      523
      Why do you feel you want that? I could see for a 4x4 or something. But not for a PT car. The close ratio is perfect - just pick the rear gear needed for the motor and desired highway cruise.
      1971 Camaro - 406 / T56
      2016 Camaro SS convertible
      2018 Colorado 4x4

    5. #5
      Join Date
      Sep 2007
      Posts
      424
      I say "normal for most cars" meaning most stick-shifted vehicles overall. New, old, American, foreign, sporty, economic, trucks, etc.

      I'm not looking for something very close-ratio in the first few gears. For a non-competition cruiser I'd rather not be dealing with so many gears in low speed traffic. I've had close-ratio cars before and I ended up skipping gears when I drove them. I'd rather have the gears spaced out a little more and not need to.


      I know what you're thinking: 'Non-competitive cruiser' with a T56 Magnum?
      Yes. I want a strong smooth 6spd that will retrofit into a classic muscle car. Are there any other choices?


      Again, lots of modern 5 & 6-speed cars have wide-spread lowest gears. The production TR6060s in the modern GT500 Mustangs have been done this way. It's not a bizarre concept. Tremec has always offered it on their TKO 5spd trannys. They just don't offer it on the 6spds.

    6. #6
      Join Date
      Apr 2010
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      Not to be another post questioning your reasoning, but ill throw in my input...
      The close(er) ratios compared to stock gear sets are nice in a muscle/classic car because generally the muscle car community has a bit rougher running, bigger cam, etc than a newer car. The wide first-to-second spread can put you into an undesirable rpm in slow moving traffic where you are either too low in the rpm range (in second) bucking and surging, or too high in the rpm range at your desired speed. This wont apply to you if youve got a stockish LS? or other pretty tame motor.
      I had an early LT T56 from a z28 with the 3.xx first gear and ended up swapping it out for a 2.66 trans. You were shifting out of first before crossing the intersection. It was useless.
      -Chris
      '69 Corvette
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    7. #7
      Join Date
      Sep 2007
      Posts
      424
      Not to be another post questioning your reasoning, but ill throw in my input...
      The close(er) ratios compared to stock gear sets are nice in a muscle/classic car because generally the muscle car community has a bit rougher running, bigger cam, etc than a newer car. The wide first-to-second spread can put you into an undesirable rpm in slow moving traffic where you are either too low in the rpm range (in second) bucking and surging, or too high in the rpm range at your desired speed. This wont apply to you if youve got a stockish LS? or other pretty tame motor.
      Yeah, I realize that. Close-ratio boxes are for hot hi-revving (peaky) motors.

      I'm running a low-revving torque motor. I guess that's weird for PT.com. But is it really that weird for the totality of Tremec's market?


      I had an early LT T56 from a z28 with the 3.xx first gear and ended up swapping it out for a 2.66 trans. You were shifting out of first before crossing the intersection. It was useless.
      You could have kept the 3.xx trans and swapped in a taller axle gear. That's more like what I have in mind.

      Combine that with the tighter .80/.63 overdrives. The grand total gear spread (1st to 6th) will end up virtually identical to the opposite combination - the close ratio (2.66) bottom set + wide ratio (.74/.50) overdrives. It just spaces the 2nd-to-5th gears differently within that range.

    8. #8
      Join Date
      Apr 2001
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      In my Cougar I skip gears all the time around town. I don't see a big deal. Tremec builds millions of transmissions for OEM applications, so their ratios are pretty well sorted out and "normal."

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
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    9. #9
      Join Date
      Sep 2007
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      424
      I guess the answer is yes, I am the only one frustrated by the available T56-Magnum ratios.

    10. #10
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      Quote Originally Posted by mikedc View Post
      I guess the answer is yes, I am the only one frustrated by the available T56-Magnum ratios.
      I guess I don't understand the frustration. As far as I can tell, Tremec does their ratios in terms of a percentage of the previous hear. I can post up some graphs from a spreadsheet I have. All the ratios make a lot of sense when you consider the weight, power, and the typical rear end ratios found in modern (and older) muscle cars.

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
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      Dr. EFI
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      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    11. #11
      Join Date
      Sep 2007
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      424
      I've spent lots of time graphing it all out.

      Look at the ratio spread in the TKO-500. That is not a fast setup on a racetrack. It's a suitable setup to drive in the real world. (Suitable for an 8000-rpm motor and 4.11 gears? No. But for a small-cammed big block and 3.27 gears? Definitely.)


      There is no equivalent gearset for the T56-Magnum. The "wide ratio" 2.97 set does not widen the spacing between all the gears, so much as lower the bottom 2 or 3 gears as a clump. The 1st-2nd spacing is functionally just as tight as in the 2.66. The main "widening" happens between 3rd-4th (and I don't know who that appeals to).


      The TR6060s in the modern GT500 Mustangs have a 2.97 1st + the 2nd/3rd/4th gears from the 2.66 set. That's more like what I want.

    12. #12
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      Quote Originally Posted by mikedc View Post
      I've spent lots of time graphing it all out.

      Look at the ratio spread in the TKO-500. That is not a fast setup on a racetrack. It's a suitable setup to drive in the real world. (Suitable for an 8000-rpm motor and 4.11 gears? No. But for a small-cammed big block and 3.27 gears? Definitely.)


      There is no equivalent gearset for the T56-Magnum. The "wide ratio" 2.97 set does not widen the spacing between all the gears, so much as lower the bottom 2 or 3 gears as a clump. The 1st-2nd spacing is functionally just as tight as in the 2.66. The main "widening" happens between 3rd-4th (and I don't know who that appeals to).


      The TR6060s in the modern GT500 Mustangs have a 2.97 1st + the 2nd/3rd/4th gears from the 2.66 set. That's more like what I want.
      I am sure a competent builder, like Bowler can build you a T56 Magnum using the Mustang gears.

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
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      Dr. EFI
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      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    13. #13
      Join Date
      Sep 2007
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      424
      I am sure a competent builder, like Bowler can build you a T56 Magnum using the Mustang gears.
      That's what I thought too. So I called around about it.

      The unanimous answer from 4 different specialty trans shops: TR6060 gearsets cannot be adapted to work in the Magnum case. You'd have to custom-make an entire gearset for the Magnum case, which costs the better part of $10k.

    14. #14
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      Quote Originally Posted by mikedc View Post
      That's what I thought too. So I called around about it.

      The unanimous answer from 4 different specialty trans shops: TR6060 gearsets cannot be adapted to work in the Magnum case. You'd have to custom-make an entire gearset for the Magnum case, which costs the better part of $10k.
      Interesting. It's always been said that a Magnum is the same as a Tr6060, with a few small exception to make it more swap friendly. I actually have a hard time believing that the Magnum has unique gears. That makes zero sense from a production standpoint. The aftermarket is so nice for Tremec it hardly seems worth it.

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
      My YouTube Channel Please Subscribe!
      Instagram @projectgattago
      Dr. EFI
      I deliver what EFI promises.
      Remote Holley EFI tuning.
      Please get in touch if I can be of service.

      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    15. #15
      Join Date
      Oct 2018
      Location
      San Jose, CA
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      523

      T56 Magnum - am I the only one frustrated by the gearset choices?

      Well I don’t know man. I have a pretty fat torque curve 406 sbc. Yes it has a big cam and a carb and I am running 3.42 rear gears and a 26” tire. Needs a bit lower rear gear but the spacing is nice. There is always a gear for every street situation. My motor can run around 1800 on up and makes best power from 3-6K and it makes damn near 500ft lbs over that range and peaks at 520 HP

      I just did a long street cruise as part of a car show event this weekend and first gear is super useable in heavy traffic. That’s a 9.0 first gear. I think it would be slightly better for my motor with 10.0 first gear but either way it’s pretty dang useable. Used mostly 2nd gear. Hit 4th a few times which is 40+ with my setup.

      I have the same trans in a stock 6th gen with the LT1 and it works equally well with that motor.
      I wouldnt put a lower first or a bigger spread between any gear. It’s near perfect in both applications.

      I rarely skip gears in either car. If anything sometimes skip 2nd in the LT1 car and and I have skipped a gear in the 406 car more likely can skip 3rd in that one. But rarely do that in either car - there isn’t much point.
      LT1 makes a nice fat flat tq curve too. Like 450 from about 3-6K and smoother running between 1-2K vs the hot rod motor. But both motors love the T56 spread that comes in the magnum.
      1971 Camaro - 406 / T56
      2016 Camaro SS convertible
      2018 Colorado 4x4

    16. #16
      Join Date
      Apr 2006
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      while I wouldn't want a taller first gear. Especially for a high torque low reving motor. I thought you could use TR6060 gears in the magnum. My understanding is that the magnum case was specifically designed to put TR6060 gears into a t56 case so that it would be a simple bolt in transmission in all existing T56 applications. But I'm not an expert.

      This Tremec blog post is pretty informative about it. I've read it in the past but didn't reread it today. Maybe it gives some clues as to why you can't use the TR6060 gears you want?

      https://tremec-blog.com/the-differen...agnum-6-speed/
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    17. #17
      Join Date
      Sep 2009
      Location
      Ontario, Canada
      Posts
      167
      My OEM 4 speed was 2.23, 1.77, 1.35, 1.00 ... with a 3.54 axle ratio standard, 3.15 and 3.91 optional.
      Currently running the 2.66 1st T56 Magnum with 4.11 rear gears and a huge improvement over stock. I'd say it's more like the "wide-ratio" options of many muscle car 4 speeds. I wouldn't want more 1st gear.

      Ran it for a while with 3.15 rear gears and it gets more mph / gear, but with current cam it likes the 4.11s and easier on the clutch.

      If you want more mph / gear, just change axle ratio to suit your power band. Unless you're putting a low-torque, 4 banger in your car, you don't need a lot of 1st gear.

    18. #18
      Join Date
      Oct 2018
      Location
      San Jose, CA
      Posts
      523
      Yup. 2.65*4.11 is an 11 first gear.
      Your stock setup was a 9.

      Currently I’m at 9 which is a bit tall with a big cam and carb. I think 10 is pretty ideal for hotter motors and 9 is pretty good for a smooth High torque large CI motor.
      1971 Camaro - 406 / T56
      2016 Camaro SS convertible
      2018 Colorado 4x4

    19. #19
      Join Date
      Sep 2007
      Posts
      424
      If you want more mph / gear, just change axle ratio to suit your power band. Unless you're putting a low-torque, 4 banger in your car, you don't need a lot of 1st gear.
      Unfortunately my gripe cannot be fixed with any axle gear or tire size. It's a different problem.

    20. #20
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      I think you have a perceived problem, not an actual one :-P

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
      My YouTube Channel Please Subscribe!
      Instagram @projectgattago
      Dr. EFI
      I deliver what EFI promises.
      Remote Holley EFI tuning.
      Please get in touch if I can be of service.

      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

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