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T56 billet keys and sticking in 4th

 
Old 04-16-2019, 01:44 AM
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Default T56 billet keys and sticking in 4th

So,

The last T56 I was running in my turbo LQ4 T56 OBS (GMT400) truck finally got COMPLETELY stuck in 4th gear.... Broken stock stamped keys as usual.

Well, what I did was build up a 32 spline T56 hybrid, mainly because IMO the T56 Magnum and TR6060 are NOT an improvement over the old T56 due to the smaller clutching teeth of the synchronizer asemblies in the new boxes.

I built the box myself and used all the typical things to address what needs to be done, steel 3/4 fork, bronze pads etc. etc.... The "billet" keys that I was able to find ANYWHERE are likely not actually billet but powdered metal.... In fact, I got a lot of my rebuild parts from the thegearbox.org...... They sold me "billet" keys.... I **** you not, LITERALLY one of these supposed billet keys broke in my fingers as I was pulling it out of the packaging...... Long story short I called them and made them aware of this and the guy (can't remember name?) acted surprised, actually was almost in disbelief??? I mailed him some of them back and he mailed me replacements...

Well, I had to get on with it so, I used the keys that I purchased from them, including the replacements for the broken ones he later sent me.....

I should first mention that I've put maybe 10,000 miles or more on this trans since building it and 99% of the time it is absolutely flawless. Well as much as any T56 variant can be. If you've ever spent enough time around one you know how they can have a "personality"!!! Every one I've driven is notchy when cold. AND, there is a technique even then... If I slowly shift and short-shift this one it is STILL notchy... BUT, if I get the revs up real good and drive it "agressively" it is like a hot knife through butter.... Every single time.

So here is where it's at as of now:

Recently, this T56 (with the supposed "billet" keys and all the other hardcore goodies) is starting to hang up in 4th gear a bit... I can very lightly press forward on the shfiter (MGW) and it pops right out of 4th and continues to act normal otherwise...

What is going on here? My theories at this point are it is either starting to break, or has already broken the keys for 3/4 --OR-- It's slightly pushing the 3/4 keys out of the slider on the 3/4 shift sometimes and then they pop back in...

I remember someone talking about making some true, actual billet shift keys for these gearboxes but to my knowledge it never materialized. I would certainly like to see it come to be because at some point I'm going to need to drop the T56 to put a REAL clutch in to handle the power this boosted 6.0 makes in this fullsize truck. I would like to pop in some keys that are actually billet steel machined from one piece, instead of the powdered metal bullshit that everyone is passing off as "billet keys".
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Old 04-19-2019, 06:02 PM
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There is no question at all, the 6060/Magnum IS an improvement, especially in the synchro department.

I had billet keys in my old T56, and they were definitely not powdered metal. Although they were installed many years ago. I'd think the big names like Tick, Liberty, DD, RSG etc etc would all sell what they claim ?

I've only ever bought stock parts from thegearbox.org, and they seemed to be fine. Which is only to be expected really.

If the the synchros are having to work very hard, either due to abuse, clutch, poor blocker action etc etc, then the keys too will get a very hard time. All the reasons why Magnums make sense because their setup is superior.

Only way to find out what's up with yours is pull it apart, because even if they are broken and no longer in place, the parts will likely be stuck on the big magnets now.
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Old 04-21-2019, 02:36 PM
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OP, as mentioned^^^^...you/we are only guessing until you open tranny up. Based on your comments about the fragile supposed billet keys you installed (read they likely were not billet) than the keys are a very likely cause

FWIW back in 05 I got a new T56 from D&D and they installed "real" billet keys along with the steel 3-4 fork. The guy from D&D said there were some "bogus" keys being sold as being billet but were not...as you found out

FWIW I have a heavy B-body LT1 I put a T56 in and a 383. Single disc clutches did not last. McLeod Twin and I never had any issues with it now years later and it has seen 100's of 1/4 mi passes running a tire
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Old 04-21-2019, 06:27 PM
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The majority of inexpensive shift keys are not billet at all. They are powdered metal and some have been heat treated (has purplish to bronze coloring). With shift keys and bronze shift pads, you do really get what you pay for. A lot of bronze pads are "casted" from molten bronze and not billet at all. In most cases, the cheaper bronze pads are actually worse off than using the factory plastic pads as they get hot and begin to melt when coming in contact with the stronger steel sleeve.
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Old Yesterday, 01:07 AM
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Originally Posted by stevieturbo View Post
There is no question at all, the 6060/Magnum IS an improvement, especially in the synchro department.

I had billet keys in my old T56, and they were definitely not powdered metal. Although they were installed many years ago. I'd think the big names like Tick, Liberty, DD, RSG etc etc would all sell what they claim ?

I've only ever bought stock parts from thegearbox.org, and they seemed to be fine. Which is only to be expected really.

If the the synchros are having to work very hard, either due to abuse, clutch, poor blocker action etc etc, then the keys too will get a very hard time. All the reasons why Magnums make sense because their setup is superior.

Only way to find out what's up with yours is pull it apart, because even if they are broken and no longer in place, the parts will likely be stuck on the big magnets now.
Stevie, I always appreciate your input man, you're obviously a smart and capable dude with a cool AND fast car. However, (here's my disclaimer first) I mean no disrespect by ANY means... I'm just not sold on the idea that the 6060/Magnum is an improvement...

Post #14:
https://ls1tech.com/forums/manual-tr...vs-tr6060.html

This is the T56 "hybrid" that I am currently running, I built it myself based off of the article this gentleman was nice enough to share:
https://www.eecis.udel.edu/~davis/z2..._Fbody_T56.pdf

This T56 I'm running, like in the hybrid build link I posted above, uses the 32 spline mainshaft and the triple cone synchros in 1-2 and double cone synchros in all other gears. So, if I'm not mistaken, the synchros are very similar in that regard between the T56 and the TR6060/magnum. Other than the clutching teeth being smaller in the 6060/magnum.

Yeah you're probably right about thegearbox.org selling stock stuff. But to me, if they market something as a billet shift key, it ought to be that. From what I can tell the "billet" shift keys they sell are only powdered metal. Now someone with a better understanding of metallurgy than I can probably correct me if necessary, but, I would think that even the powdered metal keys would be an improvement over the stamped steel keys a lot of T56s used.

I'm going to run this one either until I have to drop it for some reason, OR I drop it for a clutch install...



Originally Posted by ****** View Post
OP, as mentioned^^^^...you/we are only guessing until you open tranny up. Based on your comments about the fragile supposed billet keys you installed (read they likely were not billet) than the keys are a very likely cause

FWIW back in 05 I got a new T56 from D&D and they installed "real" billet keys along with the steel 3-4 fork. The guy from D&D said there were some "bogus" keys being sold as being billet but were not...as you found out

FWIW I have a heavy B-body LT1 I put a T56 in and a 383. Single disc clutches did not last. McLeod Twin and I never had any issues with it now years later and it has seen 100's of 1/4 mi passes running a tire
Yup. Like I said, gonna run it till I can't and/or it's clutch upgrade time then open it back up and see if those keys broke. Even if they didn't, I'll likely upgrade them anyways. Yes, I put a stell 3/4 fork in mine, can't remember actually, maybe the donor trans I built up actually came with a steel fork, but either way.

I never run this thing down the 1/4 and don't really care to. It's just a fullsize truck with all the creature comforts that you can load up a stack of plywood and go stomp *** on 90% of what you encounter on the streets if so desired. That's enough for me.

Originally Posted by AMP-D View Post
The majority of inexpensive shift keys are not billet at all. They are powdered metal and some have been heat treated (has purplish to bronze coloring). With shift keys and bronze shift pads, you do really get what you pay for. A lot of bronze pads are "casted" from molten bronze and not billet at all. In most cases, the cheaper bronze pads are actually worse off than using the factory plastic pads as they get hot and begin to melt when coming in contact with the stronger steel sleeve.
Interesting. Thanks for the input.
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Old Yesterday, 11:44 AM
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Just because one box may say double synchros, doesnt mean they are the same. Much like a T5 has synchros and gears...doesnt make it as strong or as good as a T56. Because they're totally different.

The Magnum has wider gears. The synchros are larger diameter meaning the blockers have an easier time, more teeth to engage for the synchros at the larger diameter...all of these things are positives.

So no a T56 is only similar in that is has gears and synchros...much as a T5 is similar, etc etc. Similar is not the same though

The Magnum is better in every regard.
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Old Yesterday, 03:21 PM
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Yeah the magnum has wider gears. but the case dimensions stayed the same so something had to give which were the clutching teeth like in the post I shared above. No matter how good any of us are at rowing gears, and how good of shape the trans is, the hydraulics, etc, sometimes the synchronizers just don't cooperate and a missed shift is always a possibility. LS123, the same guy in that same post also states that in his opinion the sintered bronze blocker rings in the magnum are not an improvement over the carbon fiber ones from the T56.

What does all this mean? I don't know. I'm not a professional trans builder by any means. Just a shadetree guy. I will say this though, I've been in a few T56s before, rebuilt a couple of them, and built up this 32 spline triple cone hybrid I'm currently running... The gears in a T56 are already pretty massive. In my non-expert-non-professional-trans-builder opinion the gears weren't really the weak point of the T56 anyways. It was the 27 spline mainshaft breaking on hard launches and/or in heavy vehicles the T56 was swapped into. Also, the input shaft was a failure point from the fluid rushing away from it on a very hard launch and starving it of lube. I TIG welded an AN fitting on the case of this T56 to spray lube directly at the headset gears.

Funny you mention the T5. I have fiddled around with a T5 once and if there is one thing I can definitely appreciate about the T56 or the Magnum is the fact that you assemble those on the front plate then pull the case down over it like a shirt. A T5 is like building a ship in a bottle by comparison lol. I once rebuilt a Ford sideloader 3 speed with a Borg R10 overdrive behind it. That thing was also like building a ship in a bottle and in my opinion way more involved even though it has half the gears of either 6 speed haha.
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Old Yesterday, 04:51 PM
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Magnum has triple cones with either paper or carbon friction surfaces on 1-2 and doubles elsewhere....there is no bronze to metal as per very old transmissions. And again the larger diameter all means they will be far more efficient at doing their job.
They also have a much better version of those keys you're breaking lol.

And certainly compared to very old boxes, the 5/6 cluster setup is much stronger. That was always something I thought would break in mine, although I ended up just wrecking 5th gear instead on one box, and the 5/6 slider hum on another. Many others have stripped teeth off the input gear, although I never did that myself. So yes the standard 27 spline output is considered a weak area, but the gears themselves do also have limitations.

The Magnum is definitely just better all round. Doesnt matter what you spend on an old T56...it still wont be as good as even a standard Magnum. Would be nice if it had the internal pump like the 6060 though
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Old Yesterday, 07:28 PM
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What was the sintered bronze blocker rings he was talking about, perhaps that's just the 6060 and not the Magnum? Larger diameter gears will of course be stronger, but what do you mean by more efficient?

What about those clutching teeth being smaller? I think you're right about the Magnum being an improvement over the T56 in every regard. But those clutching teeth for me make it a wash or a tradeoff perhaps?

I see what you're saying though. The Magnum is probably the best thing in your case since you make those high speed pulls in overdrive. You're a madman lol. I can't even hold mine out all the way in 4th most of the time, that's way too fast for me lol. But again, I never track the thing, just tons of street mischief. I usually keep a bunch of miscellaneous trash, a couple sleeping bags, toolboxes etc in the bed just to add to the "sleeper" effect. I only ever use 5th and 6th for cruising to keep the revs down and help the mileage a bit so I should be good there.

I don't think the current keys in there are broken. I'm still driving it and still beating the **** out of it and it's doing fine.... It FEELS like that one time it got "sticky" in 4th that the keys started to come slightly out but popped back into the slider.

When the stock stamped keys broke in the previous 27 spline T56 it was flat out STUCK in 4th. And when I tore it down the keys were broken, no surprise. Interestingly, I had the tailshaft housing off of that last T56 in the past, BEFORE it got stuck in 4th, and there were bits of those keys stuck to the magnet. I slapped it back together and hammered on it that way for another several years before the keys finally broke enough to make it stick in 4th.

I think the thing that annoys me about the whole deal is the fact that Tremec bought the rights to the T56 from Borg and then shortly thereafter ended the production run. To my knowledge they haven't made any parts for them in quite a while either. So it seems to me that Tremec is trying to FORCE ya to buy into their magnum. But my T56 works fine and I will keep running it just because it works fine for me. AMP-D pointed me in the direction of some legitimate billet shift keys. When I ditch the LS7 clutch and put in a better clutch I will slap in some of those actual billet keys and stab the T56 back in and let it rip.

I'm glad to see alternative options popping up like the CD009 and the AR5 trans. Anything to give us more options is good for that fact alone. And, maybe things will become more affordable as the result of more competition/options? We no longer are stuck with either choosing a T56 or a Magnum because these other options exist and that is awesome I think.

A magnum costs $3,314 shipped to my door. A 4 speed Lenco or Jeffco would be just a little bit more than that, around $4,000 I think. I know it's comparing apples to oranges a little bit since one is a constant mesh cluster shaft type manual vs a planetary style lol but nonetheless. I've got 2 or 3 other T56s in my parts stash stuffed back underneath a bunch of other goodies. I was contemplating building up another 32 spline triple cone synchro hybrid for a future project but the more I think about it, I'm just going to sell them and keep throwing money into a sock drawer until something like a planetary manual would be affordable.... Add a Gear Vendors overdrive at some point or gear the rear axle in a sane fashion and you'd have the best of it all. The ability to modulate torque with a clutch, and the brute strength of a compound planetary gearset.
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