faster shifting T56

Now that I'm back employed in the transmission business its time to rebuild one of my T56s with professional help.

This will be for a road-race performing (but street-used) 67 LeMans with an LS-based engine. My problem with manuals has always been that they don't shift fast enough unless you push them hard... at which point you put fast wear on the syncros and stress the shift forks. In fact, that's what is wrong with mine... worn 2nd and 5th synchros and a worn out fork.

I thought long and hard about dog rings but everyone keeps telling me that they just can't be used on the street. I keep getting myths and internet lore about dog rings and I can't seem to get a straight answer.

I even went as far as looking into Lenco-type multi-lever planetary setups, but so far I think that's a very poor option.

So, how do I get my T56 to shift faster. I watch rally cars with their super-fast dog boxes, and I don't need that much speed but something quicker than stock.

Ideas?

I don't think anybody does it anymore, but I read articles in Hot Rod or Car Craft in the 70's where the drag racers removed 2/3rds of the teeth from the....working on terminology now....engaging teeth on each gear. Ya know, not the constant mesh gear teeth, but the engagement teeth the shift collar locks to. They might have milled teeth out of the sliding collar, as well. Now that I think about it, maybe that was the beginning of the dog box. Dunno.

I just can't imagine the strength would be as original, but apparently they shifted fast.

What would the problem be with dogs on the street? Durability, or just massive crunching noises every time you shift?

Here's a recent thread on turbo-mopar about cutting half the teeth off.

http://www.turbo-mopar.com/forums/showthread.php?60771-A568-Shifting-Mods-Crash-Box&highlight=

The guy said his shifting improved majorly and he went from ~11.5 to 10.7 ET so it seems to have helped..

Great writeup.

One of my problems is a lack of resources. Here in town there is one excellent manual rebuild shop, but unfortunately it is one of those places staffed by a bunch of old guys who don't think outside the "box"... pun intended.

Streetwiseguy wrote: What would the problem be with dogs on the street? Durability, or just massive crunching noises every time you shift?

I was told that if I ever missed a shift or my left foot didn't coordinate with my right hand it would explode. We've all done it where we let the clutch out in anticipation of the lever going where its supposed to and somebody says, "hey grind me a pound while you're at it." I was led to believe that in a car the shock of doing that will make things blow up rather spectacularly.

I'm not worried about crunching noises although it does bring up a good point - crunching means wear and shock loads on the dogs.

I was hoping that there was a happy medium - some durable yet high-friction synchro material that would match speed faster but not wear out every 20k miles.

Check out GForce Transmissions. They have parts kits for the T56, both straight cut dog-leg and helical cut. Check them out and give them a call. My friend Patrick had a straight cut dog-leg T5 in his 90 Mustang Coupe with a 396 Windsor-based stroker, and it was the coolest thing EVER on the street. If he missed a shift, it would knock the shifter back into his hand pretty hard, but the tranny was pretty durable. Rated to 1,000 ft lbs if I recall. Anyway, give GForce a call and see what they say.

+1 on calling G-Force. They build killer boxes and should be able to help you out on your rebuild.

Another idea is to look into the shift lever itself. The stock T-56 ones are pretty bad (long throw, rubber isolaters, etc) and the Hurst Competition Plus and B&M units are both drag-racer loved (plus have stops so you don't bend the forks).

Too bad they don't make one of these to go with it:

http://www.renagate.com/info.htm

Synchro/proshift/slickshift/dogring, I've driven them all on the street and did all the conversions myself. Here's my feelings on the subject...

Synchros- If you plan to shift at hi revs, oil can be too slick and clutch discs can be too heavy for a synchro to do it's job quickly. The synchro cone needs to grab the gear which also means the clutch disc needs to be slowed down as well before the gearchange can be accomplished. Using a gear oil that has EP additives can really slow the process down.

Pro-shift / "slick-shift"- Basically the same thing, opening up the "window" between the engagement lugs, making it easier to complete the shift at high speeds. Many transmissions have 30 engagement lugs, allowing removal of every other lug (and every other corresponding internal slider spline). The engagement window is about 200% bigger, and much easier to hit at speed. The number of lugs is reduced, so those that remain get a lot more wear and tear. For really high RPM applications that don't have a lot of torque, sometimes 2 out of 3 of the 30 lugs/splines are removed for an even larger engagement window. This all works great for high speed shifting, but normal wear/tear or even one clutch screwup can burr over the internal splines in a slider, now the slider won't go over the lugs or the slider splines won't slide into the splines on it's hub. The only fix is complete dis-assembly to dress up the burrs or replace parts. There is no provision to speed-up or slow down the clutch disc ("synchronize" input shaft speed with the rest of the geartrain), so all shifts come with a harsh clunk or bang unless the driver matches RPM before completing the shift. A side effect of this larger engagement window is increased lash in the drivetrain, leading to less refined manners on the street. Pro-Shift is a bit better as the stock gear lugs are replaced with much more robust parts to regain some of the lost strength of removing lugs. They can also be re-sharpened many times before needing replacement, but one missed shift can burr things up, requiring frequent maintenance.

Faceplate- Completly different design for opening up the engagement window that spreads the wear/tear over much more area. Any burrs are self-removing, and a slight angle on the engagement faces help "pull" the parts together for even quicker shifts. It's almost impossible to miss a gear. Even bumping the shifter with the engine idling just sitting in the driveway can result in sudden engagement of the drivetrain. The hardest part of a shift is pulling the trans out of the gear that it's currently in, as the slight angle on the engagement faces pulls them together while they are transmitting power. Removing torque by using the clutch (or even just a slight reversal of torque without using the clutch) is all that is needed to start a shift, completing the rest of the shift can happen almost instantly, without further thought. Simply placing a slight pre-load on the shifter while the engine bounces off of a rev limiter is enough to complete a shift without using a clutch. Without rev-matching engagement can be very harsh, so a good driver can make all the difference between winning a race or getting a DNF on a road course. For drag racing, the magic formula for survival of the drivetrain is in the clutch.

I've had them all on the street. I would not recommend the Pro-Shift type mods, just too much maintenance. If you go with the Dog Rings, I would recommend that you keep a synchro on 1st gear, as it allows you to easily slip the trans into gear with the engine running. Without a synchro, you almost have to start the car in gear to avoid the nasty clunk.

Here's a link to the most informative thread I've ever came across on the subject with regard to explaning the differences... synchro/proshift/faceplate info w/ pictures (i'm "granny" on that thread)

GRM really needs to do an article on the subject. Lots of people in the auto world have heard of proshift/dogrings/faceplating, but very few seem to actually know what they are. There are shops that do this kind of work, but it can be done at home with the right set of tools.

turboswede wrote: Too bad they don't make one of these to go with it: http://www.renagate.com/info.htm

Holy cow! I could slap one of those on an AMC Super T-10 and put it in my Javelin!!!

Javelin wrote:

turboswede wrote: Too bad they don't make one of these to go with it: http://www.renagate.com/info.htm

Holy cow! I could slap one of those on an AMC Super T-10 and put it in my Javelin!!!

Sickness would ensue.

In reply to turboswede:

They made sequential ratcheting shifters back in the early 60's, I think by a company called BIEBLER. Two lever design, one for upshifts, one for downshifts. The company was eventually bought (i think by Hurst) and the design morphed into a vertical gate. Here's a pic of a BIEBLER on a Muncie...

http://www.jalopyjournal.com/jal_mu/478e8330-0a03-abff.jpg

Another option would be to cut down the inertia of the rotating bits - as weedburner stated, synchros have to get all the rotating masses matched in speed. A lighter flywheel will help, but so will a smaller diameter clutch. Going to a twin-disc clutch can bring the masses in closer to the centerline, dropping the moment of inertia.

Never tried it, but it might be worth looking at. Twin disc setups tend to be expensive and they're not as forgiving of wear though.

weedburner wrote: Synchro/proshift/slickshift/dogring, I've driven them all on the street and did all the conversions myself. Here's my feelings on the subject...

Wow... Great writeup and good link... Thanks.

Never been in to a T56 but I've been in to other boxes I was able to take 6lbs out of a fiesta gearbox by machining nice radius on the faces of the gears and drilling holes in the webbing. We never got it in use as the car was hit hard at the track and sat a few years then junked. I always wanted to know how it would do.

In reply to Keith:

how did that t-5 fair . i know you swapped it out for the t56 due to reliability issues for the targa but i was wondering if you put the t5 back?

i have have ls1/ tremic t56 in a miata. and that should be almost the same power to weaight as the lemons project. trust me you don't need to shift too fast. the thing is going to pull so hard by the time you think about shifting you'll be doing 100mph.

i'll add another trans setup into the equation is mine. my tremic t56 magnum has dual syncros 1-4th. when I'm racing i never touch the clutch, just throw it in gear.

NineLivesJohnny wrote: my tremic t56 magnum has dual syncros 1-4th. when I'm racing i never touch the clutch, just throw it in gear.

How does that work?

I had a World Class T5 in my old 1988 Turbo Coupe that I'd shift without the clutch both up and down. Just rev-match and off you go. That was the car I practiced my heel-toe and all the clutchless shifting. Kinda miss that car...

How does that work?

Since you probably wont get a correct answer from anyone who actually does it (theyve already jumped the shifting shark), i'll step in and say that the answer to your questions is "for a while".

Conquest351 wrote: I had a World Class T5 in my old 1988 Turbo Coupe that I'd shift without the clutch both up and down. Just rev-match and off you go. That was the car I practiced my heel-toe and all the clutchless shifting. Kinda miss that car...

The TC T5 is IMO, the best factory T5 box ever produced. It's also the basis of my AMC T5 swap sitting in my shed.

weedburner wrote: I've had them all on the street. I would not recommend the Pro-Shift type mods, just too much maintenance. If you go with the Dog Rings, I would recommend that you keep a synchro on 1st gear, as it allows you to easily slip the trans into gear with the engine running. Without a synchro, you almost have to start the car in gear to avoid the nasty clunk.

Sounds like you might recommend the faceplate with synchro on 1st?

Anyone in a 2-hour radius of Austin with one of these setups that I could, uhhh, gently and delicately flog for a half hour to see what they're like?

NineLivesJohnny wrote: In reply to Keith: how did that t-5 fair . i know you swapped it out for the t56 due to reliability issues for the targa but i was wondering if you put the t5 back? i have have ls1/ tremic t56 in a miata. and that should be almost the same power to weaight as the lemons project. trust me you don't need to shift too fast. the thing is going to pull so hard by the time you think about shifting you'll be doing 100mph. i'll add another trans setup into the equation is mine. my tremic t56 magnum has dual syncros 1-4th. when I'm racing i never touch the clutch, just throw it in gear.

The T5 never got installed in the car. By the time the bellhousing had been made properly, I wasn't going to change back. So I have all the parts to put it in the car, but haven't done it. I have to say that it's difficult to justify given the strength of the two boxes, but I should probably do it at some point just for the science experiment aspect.