Best High-po Tranny?

Size isn't everything, metallurgy also plays a role as does the overall design and geometry of the supporting components, e.g. the case. Maybe it's just marketing BS, but Tremec does at least rate the T56 to 700 ft-lbs.
I've been through this several times with customers. Here's the deal with the T56....it's expensive. It really boils down to what you want to do with the car. Just about any way you slice it, it ends up costing around $4k to get a T5 or aod out of a Mustang, and then end up driving away with a T56. If you really want a 6 speed transmission, then the T56 is by far the best option. If you don't ever drag race the car on sticky tires, the T56 will work just fine. It you don't have a cam with really fat lobes, the T56 will give you better gas mileage, and less noise while cruising on the highway. That is where the fairy tale ends. It has an unrealistic reputation for strength. the T56 and the 3550 series are built to the exact same technical specs. That is to say, the gears are the same width and strength, and the bearings are the same diameter. In short, the 3550 series and the T56 are equal in their abilities. The reason the T56 gets such a good reputation is simple. It came stock in the Camaro, and for every 1 Camaro that is drag raced on sticky tires, there are 50 Mustangs doing the same with a T5. It's just a perception thing. The TKO600 will cost you at least $1000 less..eh, probably even a greater savings than that. For those of us who have quite a bit of torque, the price points are much better on the TKO stuff as well. Since most Camaro owners don't race their cars, they don't break as often. In this case, less demand means lower production volume, means much higher prices. The price points on T56 parts are approximately 3 times that of a 3550 series. For example, a 26 spline input shaft on 3550 is $68 on ebay right now. The same 26 spline input shaft on a T56 is $330. So every time you break your T56, you are going to end up spending 3 times as much as the guy who broke his TKO.

Kurt

Size isn't everything, metallurgy also plays a role as does the overall design and geometry of the supporting components, e.g. the case. Maybe it's just marketing BS, but Tremec does at least rate the T56 to 700 ft-lbs. I do agree though, the T56 swap is not cheap.
 
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The gears in both transmission are made from the same grade of steel, have the same engagement surface area, and go through the same hardening process. Any differences in torque rating between different variations of the same transmission all have to do with gear ratios. If you get a 26 spline input shaft for a T56, it has a better design than the equivalent 26 spline 3550 shaft. However, the 26 spline 3550 shaft doesn't have many failures. The case on the 3550 has a tendancy to get cracks, most of which can be fixed with a girdle. It is almost irrelevant, because it is only an issue on very high hp dedicated track cars. Keep in mind that the T56 has a lot more rotating mass, which is more relevant for a drag car.

It would be pointless to try to relay my personal experience of seeing 8 second Mustangs go down the quarter mile with a 3550 transmission. If you don't believe it can be done, that's up to you.

The bottom line is this. If you are looking for a hi-po drag racing transmission, you are going to end up with a 3550 variant. I guarantee if you call Liberty Gear, Astro, or Hanlon and say "I want a hi-po manual transmission to go drag racing with in my Mustang," all of them are going to recommend a TKO600, and not a T-56

Kurt
 
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im ordering the tko 600 this weekend.....i wanted to ask someone that has one if the shifter it comes with is decent enough?....or should i order a different one right off the bat?... thanks
 
It's ok if you just drive around normally. If you want to shift fast, it's a good idea to get a better shifter.

Kurt
thanks....think its a hurst right?....i will upgrade to a pro 5.0 or a mgw,just wanted to at least try what it comes with and feel the difference for myself,plus save a couple bucks until my next order....just dont want it to be terrible or somthing,its a street and occasional track car....
 
What about the G-Force T5? I've seen those in magazines and on the parts sites for years. I've always wondered about them in terms of shift quality and durability, especially with their high power/torque capacity claims. They aren't cheap, but it seems like you wouldn't have to spend quite as much money since you can reuse the stock bellhousing and crossmember.
 
What about the G-Force T5? I've seen those in magazines and on the parts sites for years. I've always wondered about them in terms of shift quality and durability, especially with their high power/torque capacity claims. They aren't cheap, but it seems like you wouldn't have to spend quite as much money since you can reuse the stock bellhousing and crossmember.

Everything you've read is true with exception of the inherent weakness of the third gear. They're tougher, they shift as well or better than a superduty, and it's a bolt in proposition. All of the weaknesses of the normal T5 are shifted to the one thing that they can't change... The T5 casing itself. The ones that I've seen broken, take the cases with them.

So yeah, they're stronger than a T5 Super-duty but not as strong as the TKOs or some of the other trannies mentioned in this thread.

IMO, they fit the niche of the spirited street driver with a hundred-ish (give or take) HP advantage over the stock HO output, street radials, and street oriented rear suspension upgrades.

If you plan to beat the snot out of it, I would opt for something heavier than G-Force or other tranny that reuses the OEM T5 case and configuration (including Astro).

I'll also say that I think that it's a great lightweight option for some fairly severe street driving or road race conditions.
 
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Thanks for the info! All of the choices (TKO, 3550, T56, G-Force T5, ...) are fairly expensive, so it's great to get first hand feedback on all of them.

I just checked Jegs and noticed that they have a replacement T-5 case option now. I haven't looked at these for a while, so I'm not sure when this became available.

http://www.jegs.com/i/G-Force-Transmissions/468/GFT5072/10002/-1
http://www.jegs.com/i/G-Force+Transmissions/468/GFT5-SNGF/10002/-1

Now I'm wondering how much torque/hp advantage these provide over the G-Force T5 with the stock case. This is a pretty cool potential option to resolve the case weaknesses that you mentioned. (Hopefully they're cast in the US.)
 
Thanks for the info! All of the choices (TKO, 3550, T56, G-Force T5, ...) are fairly expensive, so it's great to get first hand feedback on all of them.

I just checked Jegs and noticed that they have a replacement T-5 case option now. I haven't looked at these for a while, so I'm not sure when this became available.

http://www.jegs.com/i/G-Force-Transmissions/468/GFT5072/10002/-1
http://www.jegs.com/i/G-Force Transmissions/468/GFT5-SNGF/10002/-1

Now I'm wondering how much torque/hp advantage these provide over the G-Force T5 with the stock case. This is a pretty cool potential option to resolve the case weaknesses that you mentioned. (Hopefully they're cast in the US.)


I've no idea how much the beefier case will help. I would imagine that the third hear problem would still be an issue for high torque applications but I do not know for sure.

Maybe some of these other guys have seen this upgrade in person.
 
They charge more for that upgraded T5 case than you pay for a 3550 case. I know the 3550 case has cracking problems too. I just don't think I could get used to those straight cut gears whining all the time in G-force

Kurt
 
They charge more for that upgraded T5 case than you pay for a 3550 case. I know the 3550 case has cracking problems too. I just don't think I could get used to those straight cut gears whining all the time in G-force

Kurt

:drool: It sings right alongside by blower when I pull the car hard. :fap:


I don't have all the upgrades but I do have a T5 with straight cut gears.

I bought it used from a dude switching over to auto. Put new synchros in it before installation, slapped my Tri-X on it, and been riding the hell out it since.

What holds it all together is that my street tires are not very sticky.
 
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Here's some info from the G-Force web site. They're available with helical gears (not sure if that's a new option) and there are a lot of ratio choices to fine tune the application.

http://gforcetransmissions.com/t-5_ratio.htm
http://gforcetransmissions.com/tran_gt-5.asp

This approach to a transmission upgrade really intrigues me, especially since it only requires a clutch swap and maybe a new driveshaft yoke, and looks nearly stock. I just wish they weren't so expensive!
 
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Here's some info from the G-Force web site. They're available with helical gears (not sure if that's a new option) and there a lot of ratio choices to fine tune the application.

http://gforcetransmissions.com/t-5_ratio.htm
http://gforcetransmissions.com/tran_gt-5.asp

This approach to a transmission upgrade really intrigues me, especially since it only requires a clutch swap and maybe a new driveshaft yoke, and looks nearly stock. I just wish they weren't so expensive!

You and me both.
 
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There's no question in my mind if the T56 is stronger than the TKO. I have spent an insane amount of hours researching the subject as well looking at the turbo torque monsters and huge displacement performance cars out there. The best there was at the time was the G-Force T56. It survived behind monster turbo stangs, Vipers, camaros, and vettes when the same stangs were :poo:ting out TKOs from 3rd and 4th gear roll-ons. I'm sure tranzilla is equivalent or better than the G-force unit, but also mega-$.

I am fascinated with the T-56 magnum, though. The gear sets in that tranny are the same as the ones in the TR6060, and it will be the next tranny to go behind my turbo 331. I want to spend the money right the first time. I love the .50 rear gear for cruising - lower decibels and better fuel economy. I like the closer spacing on the other gear set, but I'd rather compromise and take the wider spacing for the cruising. My car isn't a race car... just a fast (to me) street car.
 
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We're up in the air about a T56 and a Magnum now. At first I saw some troubling news on engagement mechanisms breaking on the 6060s, but I talked to Bob Hanlon, and he said he has had no problems with his Corvette Challenge cars.

Kurt
 
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