New Tremec TKX 5 speed

Discussion in 'U-shift em' started by 87GN_70GS, Nov 6, 2020.

  1. 87GN_70GS

    87GN_70GS Well-Known Member

    Has anybody seen the new Tremec TKX 5 speed? Seems to be a game changer with a new streamlined case, 600 ft lb capability, 7500+ rpm shifting, much smoother shifting
    STREETFIGHTER50 and 69GS430/TKX like this.
  2. Looks like a great new option, especially with the A body guys in mind, Looks like the shifter can stay in the stock location.
    69GS430/TKX and 87GN_70GS like this.
  3. Stg'd 2Discover

    Stg'd 2Discover Lumpty, Lumpty, Lumpty

    Supposedly it has the stronger end loading design that the T56 Magnum 6 speed has.
    69GS430/TKX likes this.
  4. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Wow, Scott, I owe you a (root) beer! I was getting ready to order a TKO for my GS. This is the first I have heard about the TKX. You just saved me from buying something inferior. I see that American Powertrain is taking orders for the TKX at $2795, which is only $300 more than the best price I have found for the TKO. Thanks for the info!
    gs66, 87GN_70GS and BuickBullet like this.
  5. 87GN_70GS

    87GN_70GS Well-Known Member

    Seriously considering selling my brand-new, never-installed M23Z for this one
  6. B-rock

    B-rock Well-Known Member

    seems I need to get serious and decide what trans I want behind the 482 Im building. Turbo 400, 4L85E, or this one. now I really want a manual and this might be the one.
    BuickV8Mike and breakinbuick11 like this.
  7. knucklebusted

    knucklebusted Well-Known Member

    M23Z as in the 2.98 first gear? I'd be interested in that.
  8. 69SkylarkGS

    69SkylarkGS Well-Known Member

    Anyone install one of these? I was planning on doing an M22Z in my car eventually but would love a 5 speed that requires no modifications to the floor of my 69GS. It’s an original bench seat 4 speed car.
    Waterboy, Dano and 69GS430/TKX like this.
  9. BillA

    BillA Well-Known Member

    I think they literally just started shipping the TKX about a week ago. I wish they were available about 5 years ago, before I hacked my floor to install the TKO.
    69GS430/TKX likes this.
  10. Gary Bohannon

    Gary Bohannon Well-Known Member

    The 600 looks like a great tranny and shifter design.
    The TKX 5th gear is .82 or .64.
    So be carefull.
    Don't buy an incorrect gear choice at that price!
    3.42 x .82 is a 2.80 final ratio
    3.42 x .64 is a 2.19 final ratio! Full throttle could = detonation.
    I would avoid a final ratio above 2.80 on a stick shift, and even that is more than I would want.
    3.73 x .82 is a 3.09 final gear, and I could live with that.
  11. Bens99gtp

    Bens99gtp Well-Known Member

    Yeah that .64 is alot of reduction.....but would work great of 4.33 or 4.56 gears. Lol
    72gs4spd likes this.
  12. 69SkylarkGS

    69SkylarkGS Well-Known Member

    I appreciate the heads up I didn’t even think about that. My rear is the factory 3.42 posi. With it being the Buick only 8.2 I’m stuck with those gears unless I swap the whole thing.
    69GS430/TKX likes this.
  13. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    Yes, when I checked their site yesterday it says "in stock, will begin shipping Dec. 30."
  14. 69GS430/TKX

    69GS430/TKX Silver Level contributor

    OR .72, which might be a good compromise for many setups. It's what I am probably gonna order, since my GS has a 3.64 rear end (I think).
  15. Stg'd 2Discover

    Stg'd 2Discover Lumpty, Lumpty, Lumpty

    If I had 1 overdrive to choses from, I would get the .82 5th, otherwise go with a 6 speed if you do a lot of varied driving that also includes quite a bit of higher speed interstate. The spread between .62 and 1:1 is a lot of rpm drop. On my 6 gear with a 3.73 and 26" tire,( which is the same as a 4.10 with a 28") I use 5th a lot of the time in traffic to keep in a power band where there is minimal carburator idle circuit to power circuit transition with my radical cam. Higher performance cams with lower idle vacuum, can be tricky to tune in transition and you could feel pulsing more with a stick car where as an automatic's hydraulic action will absorb them better.

    On the other hand with a milder combination and very torquey low rpm engines with fuel injection a .62 ovedrive could possibly work out.
  16. 72gs4spd

    72gs4spd Well-Known Member

    I’m thinking of the .81 overdrive with the 2.87 first gear. I have 3.73 with a 27.3” tall tire. Their website also says out of stock till late December, but I’m in no rush.
  17. 69SkylarkGS

    69SkylarkGS Well-Known Member

    What would y’all recommend with the 3.42 8.2 rear? I currently have the original Muncie M21 in it. Its a little leaky but shifts fine lol, not too bad for being 50 years old. I just don’t like the 2.20 first gear and don’t want to destroy the original transmission either. Plan was to put an M22Z in it eventually. Car has Nitto NT 555Rs on it that are 275/60R15 (27.76 diameter). Mild 455 about 10 to 1 with a TA 290 94H cam, small valve heads (will eventually buy aluminum down the road when possible), headers, etc.
    69GS430/TKX likes this.
  18. SpecialWagon65

    SpecialWagon65 Ted Nagel

    What would first gear feel like though? 12.5 starting line ratio?
  19. Bens99gtp

    Bens99gtp Well-Known Member

    I know what feels like with 4.56 on a th400. That's like 11:1......coming off the transbrake at 3500 you grabbing 2nd gear just as fast as your hand can get back
  20. TrunkMonkey

    TrunkMonkey Well-Known Member

    FWIW, sort of apples to oranges BBB vs nailhead.

    I have a TKO 500 (wide ratio) with .68 OD in my '64 with the nailhead and a 3.55 rear, so final is 2.40.
    First is 3.27 so starts are very easy, and it will smoke 'em 130 feet from a dead stop in second from a 3,000 RPM dump.
    Purs on the interstate at about 2500-2800 at 80-90 (yeah, you'll get run over if you drive posted)
    gs66, docgsx, Dano and 2 others like this.

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