TKO or T56?

[mstennes]

Here's my delima I'm almost ready to start tearing out my old 383 and 2004R and I picked up a a LS7 and cant decide which way to go TKO 5 speed or a T56 6 speed, what is the best setup for this engine? Its going in my 69 Camaro if that helps.
Thanks,
Mike

[Bandit]

Since no one else wants to play, let me give you my 2 cents' worth: I say TKO 600 5-spd, that's what I went with for my big block Trans Am.
From research I've done it seems that the TKO is a bulletproof tranny and the "downside" of having 1 less gear is really not an issue, IMHO, unless you plan on running 4:50+ rear gears or plan on going 200 mph.

Paul

P.S. To be fair, I can't vouch for either one personally yet, I am waiting for my driveshaft to get here to try out my TKO, I am just going off of what I have read in other reviews.

[coolwelder62]

I had a tko in my in last 69. The thing work great w/ no problems. I used a turbo 400 crossmember & just cut the mount off the back and welded it to the front of the crossmember.The 93 LT1 was mounted in the stock location and the mount worked as if GM had wanted it too. The T56 you will have to rise your trans tunnel up some to make it fit.And shorten the drive .W/ the TKO my stock drive shaft worked. There both great trans But install what will really make you happy. Good luck.

[mstennes]

The reason I wondering is I have a T56 out of a Viper I bought off a friend a while back but it would be nothing to sell it and go with a TKO, I have a set of 4.56s that were for another project and I just kinda thought 6 speeds, 4.56's that could be fun????? I dont care about how fast it will go, anything over 140 in a convertable (anything over a 100) gets kinda interesting. So its TKO 500/600 than? What is the optimum rear ratio with a 500 horse LS7 and a T56? How about a TKO?
Thanks!
Mike

[coolwelder62]

My car had 4:11s at 70 mph 2200rpm. I had 315/35/17 rear tire 26.5 inches tall.If you have a T56 use it. good luck.Scott

[SS454]

Is that a stock T56 that you are running at 2200 rpm's at 70 mph, cause your tire size,trans, and gears are the same as my 70 Chevelle's got, I'm just waiting on the T56 to get back from the shop. I was wondering what I would be turning at 70mph.

[71Nova]

If you already have a t-56 I would use it. I like them better anyway. Both great choices. I love my t-56 and instalation was easy.

[mstennes]

Actually it wasnt out of a Viper it had Viper internals added, I decided to go with the T56. Now I need to figure out 3.73's, 4.11 or something else? Its going to be hooked up to A LS7 (Gen 3). Going in a 69 Camaro.
Thanks,
Mike

[BThibodeaux]

The 5th gear ratio in the TKO 600 is .64, and the sixth gear ratio in the T56 is .62; so they are essentially the same. Therefore, mileage and drivability is not the issue on the highway. Both transmissions shift really nicely. Both are very strong. The T56 requires transmission tunnel modifications due to it's larger size. The TKO does not. I had a T56 in my first 69, and am going with the TKO in the one I am currently building. For me, 6 gears were a bit much. I also like the idea of not having to make the tunnel modifications.

Good luck,
BT

[Mkelcy]

The 5th gear ratio in the TKO 600 is .64, and the sixth gear ratio in the T56 is .62; so they are essentially the same. . . . The T56 requires transmission tunnel modifications due to it's larger size. The TKO does not.
Viper sixth gear is 0.5:1, not .62, so there is about a 20% difference in top gear and a significant potential fuel economy advantage for the 6 speed. I did not have to modify the transmission tunnel on my '68 for the T56; maybe '69's are different.

[Steve1968LS2]

Learned today that theres way more than just one type of T56.. there's the f-body one (in newer Camaros for example).. the "viper" T56 and the "aftermarket T56"

Tremec sent me the aftermarket version which is great for bolting up to a SBC but not so much for an LS2. The input shaft is longer and as such I have to use a different bell and a host of other issues like no VSS output.

Jeff at Classic Chevy 5-speed saved my bacon by swapping it for a normal T56. Very nice of him to do.

However Im a bit bummed that it will have the .50 6th gear which makes it useless for anything except mileage. If I had know I would have gotten steeper rear gears rather than the 3.70s I got (3.90's ?).. Someday when I have it rebuilt I will change the gearing.

Oh, the T56 is smoother shifting compared to a TKO and it goes into reverse easier.

[Mkelcy]

T56 Gear Ratios

http://www.ttcautomotive.com/English/products/T-56.asp#Car

[BThibodeaux]

Viper sixth gear is 0.5:1, not .62, so there is about a 20% difference in top gear and a significant potential fuel economy advantage for the 6 speed. I did not have to modify the transmission tunnel on my '68 for the T56; maybe '69's are different.

My T56 was the aftermarket version which does have a .62 ratio in sixth gear. I did have to modify the tunnel to get it to fit.

[fatlife]

Learned today that theres way more than just one type of T56.. there's the f-body one (in newer Camaros for example).. the "viper" T56 and the "aftermarket T56"

Tremec sent me the aftermarket version which is great for bolting up to a SBC but not so much for an LS2. The input shaft is longer and as such I have to use a different bell and a host of other issues like no VSS output.

Jeff at Classic Chevy 5-speed saved my bacon by swapping it for a normal T56. Very nice of him to do.

However Im a bit bummed that it will have the .50 6th gear which makes it useless for anything except mileage. If I had know I would have gotten steeper rear gears rather than the 3.70s I got (3.90's ?).. Someday when I have it rebuilt I will change the gearing.

Oh, the T56 is smoother shifting compared to a TKO and it goes into reverse easier.

They actually have 2 differnet T56's from F bodies, the 93-97 LT1's and then the 98-02s, the first gen, have the closer ratio spread, and have the steeper overdrive but are weaker because of this, I think they are rated at 350ilbs of torque while the LS1 is 450. The LS1 tranny is what you got with the more spread out gear ratios. Then you have the viper which is basically just a beefier output shaft and gears and uses the LS1 gear spread. I think the aftermarket version is the same as the first gen of the F body version.

Also I would think a T56 would be harder to put in reverse because they have a solenoid that helps engage reverse, that can only be operated with a PCM, it engages below 5mph. And when you put a T56 into a older car, you know have no help from the solenoid, and have to slam it over to get it into reverse. Probably hard for your old lady, but thats about it.

And your going to hate those gears, I have 3:73's in my 454 and it lugs and pings bad in 6th gear, its not even usable, not sure if your LS2 is stroked or not or what cam you have, so if you don't have a bunch of low end power, your def gonna want to move up to 4:11's. However you do have fuel injection etc, so I'm sure the computer will help out when it senses anything, so maybe your good. Thing about it is that on my car the 3:73's definetly help me launch the car, easier to not spin the tires, which is nice with over 600hp, but it just takes too long to get into the power band and rev out. BTW I do have a pretty huge cam, so that may be the reason of the bad drivability in 6th, changing gears isnt' hard or expensive, unless you need a different carrier so if you don't like them you can just change them out.

[USAZR1]

However Im a bit bummed that it will have the .50 6th gear which makes it useless for anything except mileage. If I had know I would have gotten steeper rear gears rather than the 3.70s I got (3.90's ?).. Someday when I have it rebuilt I will change the gearing.

Oh, the T56 is smoother shifting compared to a TKO and it goes into reverse easier.

Better mileage is all a .50 6th cog was designed for,Steve. Back in the day,us older guys running 4.56 or 4.88 gears would have killed for a T56.
My 69 has a D&D Viper T56 with 4.11 gears and it works very well.

[Mkelcy]

Also I would think a T56 would be harder to put in reverse because they have a solenoid that helps engage reverse, that can only be operated with a PCM, it engages below 5mph. And when you put a T56 into a older car, you know have no help from the solenoid, and have to slam it over to get it into reverse. Probably hard for your old lady, but thats about it.

You can get a shift knob like the one in the link and wire the switch to the reverse solenoid. Press the button and shift into reverse easily.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=HUU%2D1630052&N=700+400134+4294862546+4294906189+4294864531+4294 862462+4294862271+115&autoview=sku

[Steve1968LS2]

And your going to hate those gears, I have 3:73's in my 454 and it lugs and pings bad in 6th gear, its not even usable, not sure if your LS2 is stroked or not or what cam you have, so if you don't have a bunch of low end power, your def gonna want to move up to 4:11's. However you do have fuel injection etc, so I'm sure the computer will help out when it senses anything, so maybe your good. Thing about it is that on my car the 3:73's definetly help me launch the car, easier to not spin the tires, which is nice with over 600hp, but it just takes too long to get into the power band and rev out. BTW I do have a pretty huge cam, so that may be the reason of the bad drivability in 6th, changing gears isnt' hard or expensive, unless you need a different carrier so if you don't like them you can just change them out.

I don't know.. I had 3:73's in my 2000 SS and 6th was usable, although the think was such a low RPM that it was an MPG deal only.

Like I said, if I had known I was going to end up with a .50 T56 I would have got to 3.90s.. eventually I will rebuild the trans to the gearing I want. Right now I just want it DONE!! lol - Will see how this goes and then adjust the gears or the trans from there. It's a process :)

Must be your cam. stock 4th gen Z28s have a .50 6th and they are quite drivable (although sluggish given the low RPM).

[Steve1968LS2]

My T56 was the aftermarket version which does have a .62 ratio in sixth gear. I did have to modify the tunnel to get it to fit.

What was it hooked up to? My problem was that the clutch, shifter, SFI bell and all that jazz was the same as a new F-body uses.. to run the aftermarket T56 I would of had to swap most of that out. I don't think (the one I had) aftermarket T56 even has the VSS deal and it certainly doesn't plug into the LSx wiring harness.

[Teetoe_Jones]

They actually have 2 differnet T56's from F bodies, the 93-97 LT1's and then the 98-02s, the first gen, have the closer ratio spread, and have the steeper overdrive but are weaker because of this, I think they are rated at 350ilbs of torque while the LS1 is 450.

Not accurate. The 93 T56 from the F body is the only one that was rated lower at 400 ft lbs, and used a different gear ratio. The 94-02 T56 all were rated at 450 ft lbs, and use the 2.66 1st, and .5 6th.

Also I would think a T56 would be harder to put in reverse because they have a solenoid that helps engage reverse, that can only be operated with a PCM, it engages below 5mph. And when you put a T56 into a older car, you know have no help from the solenoid, and have to slam it over to get it into reverse. Probably hard for your old lady, but thats about it.

All that needs to be done fix this is hook up the pig tail to any 12V switched source. No PCM is needed. We typically wire street cars to the brake light swithc, that way anytime you apply the brakes, you can put it into reverse.

And your going to hate those gears, I have 3:73's in my 454 and it lugs and pings bad in 6th gear, its not even usable, not sure if your LS2 is stroked or not or what cam you have, so if you don't have a bunch of low end power, your def gonna want to move up to 4:11's. However you do have fuel injection etc, so I'm sure the computer will help out when it senses anything, so maybe your good. Thing about it is that on my car the 3:73's definetly help me launch the car, easier to not spin the tires, which is nice with over 600hp, but it just takes too long to get into the power band and rev out. BTW I do have a pretty huge cam, so that may be the reason of the bad drivability in 6th, changing gears isnt' hard or expensive, unless you need a different carrier so if you don't like them you can just change them out.

I'd say your Carb and Cam are the main reason for these 6th gear issues. The LSX engine with EFI will have none of these problems.

Tyler

[fatlife]

Not accurate. The 93 T56 from the F body is the only one that was rated lower at 400 ft lbs, and used a different gear ratio. The 94-02 T56 all were rated at 450 ft lbs, and use the 2.66 1st, and .5 6th.


I'd say your Carb and Cam are the main reason for these 6th gear issues. The LSX engine with EFI will have none of these problems.

Tyler

That info on the trannies goes against everything i've seen and read, but you know more about this than I do, so I suppose I am wrong on that, and you are right about cam and carb, but I thought I recalled that steves motor had a fairly big cam and heads? Even if it didn't I figured the FI would take care of it. IF not he should have no problem with the overdrive, but a steeper gear ration would still be better for performance

[fatlife]

All that needs to be done fix this is hook up the pig tail to any 12V switched source. No PCM is needed. We typically wire street cars to the brake light swithc, that way anytime you apply the brakes, you can put it into reverse.

Tyler
That sounds like a great idea, but if you ever use the brakes and gas at the same time I suppose you could accidently shift into reverse, but I doubt that would happen. I don't mind slapping mine over into reverse

[71Nova]

That is how I have mine wired. Brake light. I have never acidentely shifted to reverse. If I am on the brakes and shifting at the same time I am down shifting so no real risk of ending up in reverse. If your woried about it you can wire it to a switch/button on your dash or a button on your shifter.

[93Polo]

Not accurate. The 93 T56 from the F body is the only one that was rated lower at 400 ft lbs, and used a different gear ratio. The 94-02 T56 all were rated at 450 ft lbs, and use the 2.66 1st, and .5 6th.




The 93 F-bodies also have 2 different sets of gear ratios depending on if the car had 3.23s (400 ft lbs) or 2.73s (360 ft lbs) from the factory.

http://www.f-body.org/faq/4/4_3.htm

I also believe the CTS-V and GTO T56s bolt up like a LS1 f-body but have the Z06 M12 ratios lower 1st and shorter 6th. I would have to look it up to be sure.

[MarkM66]

I never wired up my reverse lock out. I guess I just got use to it, :) .

[BThibodeaux]

What was it hooked up to? My problem was that the clutch, shifter, SFI bell and all that jazz was the same as a new F-body uses.. to run the aftermarket T56 I would of had to swap most of that out. I don't think (the one I had) aftermarket T56 even has the VSS deal and it certainly doesn't plug into the LSx wiring harness.

Steve,
My T56 trans came with an adapter plate which allowed you to bolt it directly to the pre-LS1 SBC bellhousing. This is the reason for the longer input shaft. I had a ZZ4 motor, Lakewood bellhousing and manual clutch. The tailshaft on the aftermarket version was also different, as it came with a speedo gear, and allowed for the stock speedo cable. Probaly not something you would want to try to make work with an LSX motor.

Is this the info you are looking for?