TKX vs T56

[DentalDart]

Care to shed some light on why someone would choose 1 over the other?

Is one more comfortable to drive? Or more fun to drive?

If you start explaining gear ratio numbers I will not know or understand anything you’re saying so say it is stupid people terms like you have to shift out of first fast, your car loses power when shifting into last gear.

Photo for fun… 70 degrees and sunny in SW Missouri for Christmas.

 

[340sFastback]

T56 has better gearing and two over drives. But T56 is around 50 pounds heavier, a bit larger in size, and a bit more expensive. TKX is very good trans

 

[72bluNblu]

I mean, beyond the extra gear?

The TKX still requires tunnel and crossmember work, but substantially less than the T56 needs. My rationale for the T56 was that if I was cutting and welding I was cutting and welding. I was comparing to a TKO though at the time because the TKX wasn’t a thing yet. While the TKX takes less modification it’s not like the car stays stock.

The T56 magnum (aftermarket version) is good for 700 ft/lbs of torque, so, 100 more than the TKX if that matters.

The T56 is also widely supported, I know there’s a couple different versions though and not everything interchanges. But some of the production models are pretty beefy and there’s a lot of support. The TKX is based off a T5 so there’s lots of production on the T5 as well, but the production T5’s aren’t that strong and I don’t know how useful any of the production parts are for the TKX. Either way if you’re not beating hard on the transmission the aftermarket support might not matter too much for either one.

With the T56 in my Duster I have the .80 and .63 overdrive gears. Even with that set up, 4.30’s and 27” tall tires I typically only get into 6th on the freeway. Most of the time I’d manage just fine with only a .8. But it is nice having the extra gear and I probably wouldn’t have gone to 4.30’s if I didn’t have the .63 as well.

 

[DentalDart]

T56 has better gearing and two over drives. But T56 is around 50 pounds heavier, a bit larger in size, and a bit more expensive. TKX is very good trans

I don’t understand the gearing. Most of my shifting will be up to 60 mph on side streets, not much freeway driving, maybe 10-15 minute freeway drives every couple of months.

The OD of the 56 I’ve read mixed reviews, people saying 6th isn’t usable unless going 70+ mph or on long drives?

 

[340sFastback]

I don’t understand the gearing. Most of my shifting will be up to 60 mph on side streets, not much freeway driving, maybe 10-15 minute freeway drives every couple of months.

The OD of the 56 I’ve read mixed reviews, people saying 6th isn’t usable unless going 70+ mph or on long drives?

There are two T56s one wide ratio and one close ratio. Then the torque curve of engine and rear gear ratio come into play. So 6'th isn't usable means the trans and rear gear aren't matched to the engine. So yeah if someone doesn't have a clue what they are doing when they built their car we can have cases where 6 is not usable.

 

[DentalDart]

There are two T56s one wide ratio and one close ratio. Then the torque curve of engine and rear gear ratio come into play. So 6'th isn't usable means the trans and rear gear aren't matched to the engine. So yeah if someone doesn't have a clue what they are doing when they built their car we can have cases where 6 is not usable.

Ok so say the engine is a 470 or 499…. 3.55 rear gears… idk if those are the best gears but it’s a set I was thinking…

 

[1WildRT]

5 speeds = really good acceleration from a dead stop to over 90+ MPH
6 speeds = really good acceleration from a dead stop to over 140+ MPH

6 speed is considerably bulkier requiring more tunnel modification....

Both are extremely fun....

 

[DentalDart]

5 speeds = really good acceleration from a dead stop to over 90+ MPH
6 speeds = really good acceleration from a dead stop to over 140+ MPH

6 speed is considerably bulkier requiring more tunnel modification....

Both are extremely fun....

This is perfect. I’m never going that fast lol

 

[72bluNblu]

Ok so say the engine is a 470 or 499…. 3.55 rear gears… idk if those are the best gears but it’s a set I was thinking…

With a 470 or 499 you’ll have more than enough torque to use 6th gear and drop the rpm’s down for extended freeway use. Run some 3.91’s and a T56 with a .63 6th.

Keep in mind that the production T56’s are usually the .50 6th, so even lower rpm’s at speed, and those are what modern Challengers run with Gen III hemi’s. And Camaro’s, etc.

 

[340sFastback]

My setup is 414 small block stroker 500 hp and 500 tq, T56 close ratio 2.66 first gear .63 six'th gear, I had 391s but dropped down to 373s when Dana got swapped in, 27 inch tall tire. Its basically like a close ratio 4 spd with two over drives. When I up shift through first 4 gears RPMs don't drop much keeping engine in max torque curve. Higher speed roads 5'th gear cruising. I can cruise on highway 70-80 mph engine is quiet can pull steep grades no down shifting needed. Its basically no compromise ANYWHERE speed wise. All the acceleration tire burning fun through first 4 gears and ultra comfy high speed cruising. The 6 speed is much better then I had expected so glad I did it.

You are not going to get as close of gear ratios in a TKX which means bigger RPM drops on upshifts less tire burning fun. So the TKX is a compromise compared to a T56 which does not give up any performance either low or high speed driving. To me if you want the best in terms of gearing for acceleration AND high speed cruising the T56 out shines the TKX.

 

[Car Nut]

I personally prefer the TREMEC TR-6060 over the T56, if you wanna cut it up, go big or go home. Handles way more torque and horsepower. If you want an easier install, you can’t go wrong with the TKX. When I drove the 6 sp. new Challenger, I hardly ever used the six speed.

 

[72bluNblu]

I personally prefer the TREMEC TR-6060 over the T56, if you wanna cut it up, go big or go home. Handles way more torque and horsepower. If you want an easier install, you can’t go wrong with the TKX. When I drove the 6 sp. new Challenger, I hardly ever used the six speed.

The TR6060 is internally similar to the T56 Magnum, which is the aftermarket version. That’s the 700 ft/lb rating, it’s not better than that. And I believe the 6060 has the .50
6th. Maybe not but the challenger has sub 4 rear gears so unless you’re doing 80+ on the freeway 6th won’t be super helpful. But just don’t run that rear gearing, problem solved.