Hey all. Yes, it's time for that question once again. Despite my search for answers, this debate on what transmission to go with continues.

Here's the deal. The 305 in the car I have is in need of a rebuild. Naturally, I interpret that as a good excuse to drop a 350 into it. I will be dropping a stock L31 into it for the time being, and probably throwing a meaner cam into it later on. However, I know the stock T5 is an issue once that time comes, but I'm willing to baby it/risk it w/the L31 while it's stock.

Between upgrading the T5 w/GForce parts (It's my understanding that the case is the main weak point), converting to T56, or going TKO, which is the best option for me? I'd prefer whatever is gonna be the easiest installation-wise/allows me to re-use as much T5 stuff as possible (including hydraulics, if possible).

I don't see my build exceeding 350-400 flywheel HP, so I think any of these options will work power-wise, but I basically need to know if you can get away w/just a case upgrade on a T5 w/that kind of power, and if not, what's gonna be cheaper/easier between the T56 and TKO? Thanks!

 

Built T5: stock case can hold 450 HP if you upgrade the internals. It'll take over 500 if you don't do clutch-dumps at redline on slicks.

 

Stock case cant hold 250hp from the factory because the case was always the weak link to begin with. I dont agree with that at all. You can make a stock T5 work with a very high power setup, though, if you have a sense of mechanical sympathy. Dont expect it to hold clutch dumps on slicks. Be careful with the 2-3 shift because 3rd gear is the one in the middle of the two shafts, they start to bend apart and fail. 3rd gear is the weakest. Keep that in mind it will last a while, it will last probably forever if you're just commuting. But for aggressive driving without concern, Im not even sure the most built t5 wouldnt disappoint you just as quickly as a stock one.

If it were me... I would throw the stock T5 behind even a cammed Vortec 350. It will last a while, just save up for a T56 while youre at it. It will last as nicely as you drive it.

T56 will require a new crossmember, new bellhousing, new shifter, new hydraulics, new clutch, a new flywheel, and a digital speedometer conversion box. Not a cheap endeavor.

 

InfernalVortex - That confirms what I've read numerous times - The case is the weak link, and third gear isn't helping much either. But so far, some of the people I've heard complain about the Gforce stuff didn't bother to upgrade the case. What if you upgrade the case w/stock gears? Shouldn't that help it out?

I keep hearing mixed opinions on the TKO stuff as well. I'm pretty much torn between either..

A - Upgrade the T5 case and do a rebuild while the motor is out of the car

or

B - Run the T5 'til it blows up, while saving for a T56 swap.

 

whats you budget? the tko will run you almost 3 grand since you will be hard presssed to find a used one with all the converiosn parts. It also does not fit in the tunnel very well since its so tall. It took some work to get mine to fit right.

An upgraded case will keep the t5 together better. Honestly, if your not using drag radials/slicks and racing the car, the t5 will do ust fine as it is.

the t56 can be done cheaper than the tko, but will be used, requires a different crossmbmer and some other little work to fit

 

Well, use-wise, the car is pretty much strictly gonna be street use. Maybe I'd take it up to the strip once in awhile to see what it'd run in the 1/4, but no drag slicks or 500+ rhwp setups are in the picture. Street tires only. I'd just like the car to be able to do some occasional WOT and burnouts without the tranny blowing to pieces is all.

Budget-wise, I'd prefer to keep any tranny swaps/builds around $2k or less if possible. Used T56's are quite hard to come by in my area, so if I went that route, I'd most likely be stuck getting a rebuilt unit on ebay or from a tranny shop in the area. And then there's still all the conversion pieces as you say.

I've seen pics of the G-force T5 case, and it looks quite a bit beefier than the stock case, but I haven't really heard any stories about it yet. I've heard a few stories of bad experiences w/G-force stuff, but those examples have involved upgraded gears in a stock T5 case, and high HP setups too. It's my understanding that the case flexing under load is what causes the vast majority of T5 failures. It's also my understanding that a stronger case is the main reason the T56 is that much stronger than the T5.

 

Right this minute I have a friend with a dyno-proven 378-RWHP 383 running a stock '91 T5, and drag radials. Neither of us have hurt the trans. Guess some folks don't drive the way we do? Power-shifting isn't driving, it's abuse. Anyone want to confirm this car, come on out to the local Sonic.

 

The case flexes bc of the helical gears forcing themselves apart. The case has to fight this. The gforce gears use a straight cut or reduced helix gearset to reduce this effect there by taking strain off of the case.

I wouldn't drag race on one. The case to me wouldn't seem to do much good. Do some searching and you'll see why. Plenty of people road race on built T5's though without issue. Just can't wheel hop and power shift them.

I contemplated these same 3 options myself for some time. I now have a T56 sitting in the garage waiting to go in.

 

86 T/A - What all did you have to do to get your TKO to fit right? Were you able to re-use any of your T5 stuff or do you have to buy new everything to convert it? I ask because I see TKOs go for around $2200 new, but understand other parts you need can add up.

And what all other than the crossmember do you need to do to install a T56? I heard you need a new bellhousing and clutch (Even if I stick w/a T5, a new clutch is going in w/when the motor is swapped), but I also heard that you can re-use the T5 pedals and also the master/slave cylinders, you just need longer hydraulic lines for them.

 

Sorry to say AV, but you said that backwards. Helical cut gears send the load Axially, while a straight cut (or spur gear), sends the load radially. The muncies of the 60s and 70s had aluminum cases, and the M22 (rockcrusher) even tho they had a heavier gearset, would blow the gears apart just as easily as the M20 or M-21, because the case would allow the countergear in time to "stretch" away from the mainshaft. however the M-22 is a great road racing tranny, when not subjected to the abuse of hi-RPM, hi-horsepower, clutch dumps with sticky slicks. I'm sure that's what you intended to mean.

 

T5 - A joke, numerous people who have bought into the gforce "upgrades" only to end up with metal soup.

TKO, good choice, lot better choice for the $

T56, same as previous, but +1 gear.

 

you need a 3rd gen specific tko trans, it has a longer input shaft to it will work with the proper 1" thick adapter that bolts to the bellhousing and then mounts the trans straight up instead of kiltered like factory.

It will use the same hydraulics, clutch, bellhousing, driveshaft (different yoke for the trans, 31 spline c6 ford). You can use a stock crossmember too, but you need to upen the holes a little and space it off the frame 3/8". I used a UMI t5/700r4 crossmember and torque arm with mine.

I ended up cutting the top of the trans tunnel from about 8" back from the firewall and to just behind the shifter opening, then raised it about 1" in the back so that it slowly tapers up from the firewall to the back. that gave me enough room to mount the trans at the proper angle and use the crossmember with no shims.

The shifter location is pretty far forward on the trans. In stock form, almost 3" to far forward. The 1" adapter plate, and a shifter with a rear setback make up for that distance. I used a steeda tri-ax shifter, and origionally had a modified hurst shifter that i bought from Fortes Parts Connection, the place i bought the trans from.

You can get a adapter for a mechanical cable driver speedo for the trans, the trans already has a electric speedo hookup, but its a late model ford sender so it uses a much higher PPM signal that what we need, so you need to use a buffer box, Dakota Digital makes one, to convert the signal.

 

to be honest, i would stick with a world class t5, use a GOOD shifter and you should be just fine. A lot fo the t5 issues stem from the crappy sloppy stock shifter.

 

Thanks for lots of useful info there! From what you describe, installing a TKO doesn't sound THAT bad. I'm told you also need to cut sheet metal out of the trans tunnel for a T56 as well, so I was kind of expecting to have to do that with either of those swaps.

Currently, my T5 has a Hurst Billet Plus shifter in it, and not the stock one. Not sure how great of a shifter it is, but it looks nice, and the shift throw is way shorter/more precise than the stock shifter for sure. I personally like it. Can a TKO use the same shifter or no?

And you really think a T5 is gonna hold? I swear they're very hit and miss from all the stories I hear. Some people seem to luck out with cars running 12's or faster, and for others, they seem to break when they look at them the wrong way/manage to kill them with stock 305's.

I keep hearing more bad than good on G-force, so at this point, if the T5 does blow up, I think I'm gonna have to go TKO or T56. More leaning towards the TKO, since I can re-use my bellhousing and it has a higher TQ rating than a stock T56.

 

Yes you have to cut the shifter hole a little bigger with a T56, or cut out that area of the floor and relocate it further back just a little.

Unless you get one of the new hurst magnum T56's, with the shifter location on them being just a bit forward of the traditional fbody T56, you wouldnt need to.

 

It's a bandaid for a weak case design that allows the two shafts to move. They will still do this with straight cut gears. Straight cut gears just tolerate it better.

http://www.yellowbullet.com/forum/sh....php?p=5533082

http://www.carcraft.com/howto/116_06...n/viewall.html

I mean you can make it work, if you dont abuse it you can make it last a long time, etc etc, but the T5 just wasnt designed for the kind of torque we tend to put onto it with a relatively heavy car. It's like trying to make a 10-bolt survive behind a built 383 with sticky rubber... it may last a while, but its days are numbered, and as you can see the reasons are very similar - design constraints on the size of the parts that have to take the load.

Most people will say the same thing, drive it nicely, dont put slicks on it, dont drop the clutch, and dont power shift, and it may well last you the rest of your life. But even guys like 68strat with his relatively mundane, recently swapped 350 is having his T5 show worrying signs. Why get a manual trans if you have to worry about it so much? The great advantage of getting a manual trans is that you can really FEEL the instantaneous, brutal torque of these stout v8 engines and have a great time. If you get a trans that is inherently torque-sensitive... It would just take the fun out of it to me, either the driving it nicely or else, or the stress.


I agree, there are a lot of things the T5 can do just fine at. ESPECIALLY when you're in a sanctioned road racing series like American Iron and CMC which usually have really strict rules regarding power output and you're not constantly doing hard drag racing launches. Its stressful on the trans, but no road racer with a T5 is gonna be constantly power shifting it and launching it the way drag racers and even us street driving types will. There's a certain amount of mechanical sympathy those guys learn to race with and so the weaknesses of the T5 just dont get exploited so much in those situations. A lot of us make MORE power than the CMC-type road racing cars, and our cars can be quite a bit heavier too, don't forget that.

Personally, if I having to make this decision, I would just stick with factory parts and replace the T5 every time you break it. The cost of the GForce case and the cost of the gears makes it a total waste of time, since it's still not as strong as a T56 or TKO. T5's, for just the trans, can be had for what... $200-300 a piece? That's really not a bad number. You can replace a T5 6 times before you can buy a T56. I'd run a wc T5 and if it holds great, if you break it, get another, and save for a T56 or TKO. At least you'll know whether or not your car, with your driving style and your usage really needs something like an investment in a T56. Some guys just wont need it, at least not for a while.

I don't fault anyone for putting a t5 behind a 350 or a 383. I think some factory freaks make it out, I think some people have a better knack for mechanical sympathy, etc, I think if you HAVE a T5 and you're NOT having to spend a ton of money to retrofit it onto your new engine, you SHOULD at least try and see if it will live. But I REALLY dont like the idea of spending a bunch of money on special, noisy gears for a T5. It's like spending a bunch of money on super strong gears for a 7.5 inch 10-bolt. Doesn't matter how strong the gear steel is, you just cant make them big enough to handle the power. You run into physical constraints really quickly regardless of fancy metallurgy or design. It's not that G-Force offers a bad product, it's just that even expensive, unique approaches like that just aren't enough to overcome the original design limitations.

 

I went a number of seasons of weekly points racing at 119-120mph trap speeds on a stock T5.. Never had an issue.

Good shifter and no torque arm on the trans.

T5's are cheap, even if you do break one by letting your girlfriend or one of our younger members drive it, and they manage to miss third and blow it up, you can get another one for a few hundred dollars.


-- Joe

 

I can say the T5 has held up a lot better than I expected when I first put my 350 in my car after having read all of the T56 swap stuff. And mine isn't even a world class T5.

I have a T56 swap setup, that has been sitting there for nearly a year now that I haven't had time to put in. I will eventually put it in (possibly next month) but the T5 has held up surprisingly well during the last year.

My engine isn't a stock 350 either. It's a built 350 that I've dyno'd at 308 RWHP. And I do autocrosses in this car at least 1 to 2 times a month. While autocrossing isn't as hard on a tranny as drag racing, it's harder than street driving I would think. Now granted, I still have an open diff and haven't run on slicks yet so that might would make the T5 die faster. But after a year running on it with an open diff and street tires it is just now starting to show signs of problems. Mostly in the clutch though, it's starting to slip a little. But I do think the gears are a getting a little worn as well.

 

You have to work harder to blow up the trans with the stock unit. I raced my car at the strip twice without "beating" on the T5 and had problems with the rear bushing and seal almost immediately. The case can't take the torque... No matter what internals you use, it is a sloppy unit, and will always be a sloppy unit unless you were to machine you're own case. Get a T56.

 

So... I'm going to resurrect the dead...

Basically all i want to know is, autoX and road racing... Forget drag racing. I'm looking into the g force straight cut/ dog ring simply because (as far as i know) the t56 swap would outclass me before I could say "but!"

Any road racers had any problems? It will be behind a slightly modded 305... 300hp max... Just wondering...

Also how many t5 transmissions do you guys think I would end up going through in a season (if I stay stock)? 9 autoX events and maybe a few HPDE days at VIR.

Thanks in advance guys!

 

Road racing, you are going to be doing a lot of shifting and constant on/off throttle movement. I would recommend a TKO unit. Cheaper than a T56, and you aren't going to need the extra gear. The main problem with the T5, besides the case flex is the width of the gears themselves is significantly narrower, than those of the TKO and T56. This cannot be changed, no matter what modifications are made. Road racing even with a stock L69 would probably cause damage to the T5 pretty quickly. Just my opinion. Curious what others say...

I mangled and rebuilt my T5 twice before... To much of headache... Car is in the process of getting the TKO, and I'll let everyone know how I like it.

 

Thanks! I hope others will chime in as well... I want as much info as possible! While I'm not a total NOOB to camaros or racing I would like info and experience before I destroy my daily driver 3 times a year...

Thanks!

 

My boss Mike swears by the TKOs for racing. His road race 68 z28 has a 3550 (gen behind the TKO) and he loves it. It's been behind a bunch of different engines over the years, the most potent surprisingly is a dry sump 302 made into a 310. Thing is a monster on the track.

 

Sweet! Man I wish I had dry sump funds... Will you be road racing yours?

 

I hope to! The TKO is going in, and a Strange Engineering 12 bolt, as well as 1LE brakes on all 4 corners. I need to work on the suspension a bit, beyond where it's at now, and my 355 is being built up, but this is all on a budget myself. Anyhow, with the time, and money I've spent messing with the T5, I think I am going to be a very happy camper with the TKO, and not have to worry about pulling the transmission after a few hard runs.

 

Sounds good, I'll be following your progress...



Anybody else with some advice or info?

 

What kind of torque arm setup are you running?

I've always had a "spare T5" for when I break the one in the car. Maybe one day a 10 second pass will do it. I doubt it though.

-- Joe

 

Interesting to see this thread brought back again - Just as I start contemplating this stuff again after a hiatus of sorts from the third gen world.

Probably gone through a good 20+ threads on here, and also other forums about T5 stuff for the past couple of days. Since it's cheap enough to give a try, and I already have a T5 in my car, I think my plan is to experiment with the G-Force case for some extra strength (since the case seems to be more of the issue than the gears themselves), but otherwise leave the stock gears in. Seems like quite a few Mustang guys are happy with them, and T56 availability/pricing around me is becoming such a joke, that TKO is probably what I'd go with if I actually swapped to a new tranny.

T56/TKO/other aftermarket tranny sounds like the more reliable path for serious power, and the only route I'd go if building a serious track car, but I suppose in my situation, I'm gonna see if I can't get away w/a T5 since the car isn't going to be seeing drag slicks or heavy track abuse/track power levels. And not to sound lame, but I just don't think my driving style is gonna be pushing a T5 to the limits much. But if it does blows up, I'll just have to snag another T5 up cheap, and start saving I suppose

 

Ive killed more T5's then I can count. I drive my car's aggressively but not stupid. I'd never run another one again. I went to a TKO600, never looked back.